Hard to know what's going on.
Firstly - if there's an image in the frame - the type tool won't be able to add type into the same frame.
It's occupied by a Graphic and is a graphic frame.
You need to add a separate text frame above the image.
If there's already a Text frame there - then you need to check if the text frame is locked - you can go to the Layers panel and check for any objects that are locked - you can expand the layers by hitting the side arrow beside the layer.
If all is good - and nothing is locked
Then it maybe that the Graphic Frame or the graphic within the frame has a Text Wrap
If you can select your Text Frame and it shows a red square with a plus in it - it means it's overset.
You can go to the Object> Text Frame Options
and tick the option for Ignore Text Wrap
Of if you don't need Text Wrap for the Graphic Frame you can select the Graphic Frame and choose Window>Text Wrap to bring up the pallete.
And you may have added this to the graphic itself - so select the image within the frame by double clicking or selecting the 'donut' icon in the middle of the image.