i've never made a good signature before but i can try to help, i've practiced a couple times?
The only things I can advice is find a photo on google of what shape you want your signature to be, ex: if you want it to be a heart then google "heart outline" or silhouette / shape etc.
Open the outline into Photoshop then add your background you want inside of it. if it's a still photo i usually just open my pictures folder then drag it into photoshop cause if you do "open" in photoshop it will add it to a new window. you can still move it onto the other easily but yeah i just drag it in
Then simply just put the background layer on top of the shapes layer & right click the background layer and choose "create clipping mask"
f.y.i the background will fill in any SOLID areas, not transparent. so for ex: if the inside of the heart is transparent the background wont show inside it. so i'm assuming you would want a solid color in the shape, and the outside to be transparent.
you can easily make the background transparent go on youtube to look it up it's easier to watch & i learned it in like 5 minutes.
for an animated background you will need to "open" it, not drag it in. animation is more complex & idk how to do that. if you want to practice you can just go on youtube and type in "photoshop how to put a gif on a still image" that's what I did & i find the tutorials really helpful
just haven't quite gotten it yet.
Always create new layers w/ each new thing you do.
also when adding text it looks really nice to use the "fx options"; color gradients, outter/inner glows, drop shadows etc. just go to your text layer and click "fx" you will see all those options just experiment w/ them and they really make the text look wayy better than just a plain color.