So I'm using Adobe Stock free trial right now and I just downloaded an image with the standard license. I am planning on changing some parts of the image(but am leaving the watermark alone) in Photoshop. Is this image now officially considered mine? Does this mean that I don't have to provide copyright info for this image? If I do(have to provide copyright information), will saying that this image came from Adobe Stock suffice?
Copyright law is complicated. Penalties can be severe. If you are proposing this, I suggest you talk to a copyright lawyer, since we cannot (legally) give you legal advice. In addition, and over and above copyright law, here are the terms and conditions of Adobe Stock: https://wwwimages2.adobe.com/content/dam/acom/en/legal/servicetou/Adobe_Stock_Additional_Terms_en_US...
Thanks, and I will talk to a copyright lawyers. Are there any online ones that could help?
You need to stay in the limits of the licensing terms. As you have a legal license, you may use the picture but you will be bound by the license terms. Sometimes you need to credit, sometimes you do not need to credit. It's in the terms.