Watermark

If you're a non-techie like me, here is what I do: I just turn it into a Photoshop brush. That way, you can make it all different sizes, colors, and opacities to suit the situation.

-with its layer selected, go Edit>Define Brush Preset

ta-da!

Take a look here for instructions how to install and run Photoshop script https://medium.com/photoshop-tips/how-to-run-script-465d45031de6

Here is another option https://exchange.adobe.com/creativecloud.details.12780.watermark-for-adobe-photoshop-cc-english.html

Edit the var statements to use your watermark and settings in  "PlaceWatermark.jsx" Photoshop Scriprt

/* ==========================================================
// 2017  John J. McAssey (JJMack) 
// ======================================================= */
// This script is supplied as is. It is provided as freeware. 
// The author accepts no liability for any problems arising from its use.
/*
<javascriptresource>
<about>$$$/JavaScripts/PlaceWatermark/About=JJMack's PlaceWatermark ^r^rCopyright 2017 Mouseprints.net^r^rPhotoshop Script^rCustomize using first four var</about>
<category>JJMack's Script</category>
<enableinfo>true</enableinfo>
</javascriptresource>
*/
#target photoshop;  
app.bringToFront();  
var logoFile = "~/Desktop/JJMack.png";						// Watermark file should be large for resize down works better than up
var LogoSize = 10;											// percent of document height to resize Watermark to
var LogoMargin = 1;                                         // percent of Document height the Watermark should have as a margin
var LogoLocation = 5;										// Like a tick tack toe board 1 through 9.  1=Top Left 9=Bottom Right
var LogoRotation = -20;										// Center Logo Location 5 can be Rotated -90 through +90 degrees  + degree Clockwise - CounterClockwise

app.displayDialogs = DialogModes.NO;						// Dialog off 
var strtRulerUnits = app.preferences.rulerUnits;			// Save Users ruler units 
var strtTypeUnits = app.preferences.typeUnits;				// Save Users Type units 
app.preferences.rulerUnits = Units.PIXELS;					// work with pixels 
app.preferences.typeUnits = TypeUnits.PIXELS;				// work with pixels 
//placeWatermark(logoFile,LogoSize,LogoMargin,LogoLocation,LogoRotation);           // Place Watermark into the bottom of the document
if (documents.length) app.activeDocument.suspendHistory('placeWatermark','placeWatermark(logoFile,LogoSize,LogoMargin,LogoLocation,LogoRotation)' );
app.preferences.rulerUnits = strtRulerUnits;				// Restore user ruler units  
app.preferences.typeUnits = strtTypeUnits;					// Restore user type units    
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
function placeWatermark(Image,Size,Margin,position,angle){  
	if(!documents.length) return;  							// if no document return
	var fileObj = new File(Image);	       		         	// the passed file
	if(!fileObj.exists){  									// If file does not exits tell user 
		alert(fileObj.name  + " does not exist!"); 			// Alert User 
		return;  											// return
	}  
	try{  
		var doc = app.activeDocument;						// set Doc object to active document
		var layers = app.activeDocument.layers;				// get layers
		app.activeDocument.activeLayer = layers[0];			// Target Top Layer
		placeFile(fileObj); 								// Place in file the Watermark png file
		activeDocument.activeLayer.resize(100 ,100,AnchorPosition.MIDDLECENTER); // Insure Place did not scale layer  
		var SB = activeDocument.activeLayer.bounds; 		// get layers bounds 
		var layerHeight = SB[3] - SB[1];					// get layers height  
		var resizePercent = (100/layerHeight)*(Size/100*doc.height.value); // Percent to resize by 
		activeDocument.activeLayer.resize(resizePercent ,resizePercent,AnchorPosition.MIDDLECENTER);  // Resize width and height by percentage 
		marginSize = Margin/100*doc.height.value;			// Margin size
		var selectedRegion = Array(Array(0+marginSize,0+marginSize), Array(doc.width-marginSize,0+marginSize), Array(doc.width-marginSize,doc.height-marginSize), Array(0+marginSize,doc.height-marginSize));
		activeDocument.selection.select(selectedRegion);    // Select  document area for the logo Positioning
		switch (position){									// Align resized logo smart object layer into position
			case 1 : align('AdLf'); align('AdTp'); break;
			case 2 : align('AdCH'); align('AdTp'); break;
			case 3 : align('AdRg'); align('AdTp'); break;
			case 4 : align('AdLf'); align('AdCV'); break;
			case 5 : align('AdCH'); align('AdCV'); activeDocument.selection.deselect(); activeDocument.activeLayer.rotate(angle); break;
			case 6 : align('AdRg'); align('AdCV'); break;
			case 7 : align('AdLf'); align('AdBt'); break;
			case 8 : align('AdCH'); align('AdBt'); break;
			case 9 : align('AdRg'); align('AdBt'); break;
			default : break;
		}	
		app.activeDocument.selection.deselect();			// deselect		
	}
	catch(e) { alert(e + ': on line ' + e.line); }			// inform user of error  
	finally{ }  
} 
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 
function placeFile(placeFile) {  
    var desc21 = new ActionDescriptor();  
    desc21.putPath( charIDToTypeID('null'), new File(placeFile) );  
    desc21.putEnumerated( charIDToTypeID('FTcs'), charIDToTypeID('QCSt'), charIDToTypeID('Qcsa') );  
    var desc22 = new ActionDescriptor();  
    desc22.putUnitDouble( charIDToTypeID('Hrzn'), charIDToTypeID('#Pxl'), 0.000000 );  
    desc22.putUnitDouble( charIDToTypeID('Vrtc'), charIDToTypeID('#Pxl'), 0.000000 );  
    desc21.putObject( charIDToTypeID('Ofst'), charIDToTypeID('Ofst'), desc22 );  
    executeAction( charIDToTypeID('Plc '), desc21, DialogModes.NO );  
}

function align(method) {
	var desc = new ActionDescriptor();
	var ref = new ActionReference();
	ref.putEnumerated( charIDToTypeID( "Lyr " ), charIDToTypeID( "Ordn" ), charIDToTypeID( "Trgt" ) );
	desc.putReference( charIDToTypeID( "null" ), ref );
	desc.putEnumerated( charIDToTypeID( "Usng" ), charIDToTypeID( "ADSt" ), charIDToTypeID( method ) );
	try{
		executeAction( charIDToTypeID( "Algn" ), desc, DialogModes.NO );
	}catch(e){}
}