Thanks for the input, but I posted this because I don't own photoshop, so thats why I was looking to see if anyone in here might be willing to help out with what I'm wanting to do.
The website the other person posted should also be able to do the methods I just mentioned and the methods I'll explain next, because it seems to have most of the functions. However, I switched to Photoshop from that website a while ago, so I can only use Photoshop to explain.
https://www.photopea.com/ This is the method of using a masking film
Let's take this picture as an example
Find the selection tool you want to use (the quick selection tool or the magic wand tool are both highly recommended)
I'll first select this part as the area where I want to change the color.
There's an option to create a mask in the bottom right layer area.
After using it, the screen will look like this.
Next, we'll apply the color we want. First, click on the bottom right layer to confirm the working area is there. Then, use the rectangle tool to drag out a shape on my image to cover it up.
Note that the color of the graphic produced at this point is the color we need to apply.
Go to the bottom right layer area and adjust the opacity to between 20% and 50% depending on the shadows you want to emphasize.
Remember to click on the initial layer to confirm the working area before performing the above steps (the bottom one in the image).
After use, it should look like the image above.
First, confirm the work area.
Use the tools mentioned above to drag out the area again.
Then switch back to the rectangular layer
Then create a mask
Correctly looks like this
Then switch back to the initial layer, right-click on the area where you created the mask, and select either "Delete Layer Mask" or "Turn Off Mask" (choose according to your needs).
What it will look like after completion
If you want to change the color after it's finished, check below.
Click on the layer of the rectangular image to confirm the working area.
Then right-click on the layer and select Rasterize Layer (highlighted in red).
Top left corner Image > Adjustments > Hue/Saturation
Start adjusting
If the area you want to adjust has color, then at the beginning or when you select it, go to Image > Adjustments > Black & White
Because English is not my native language, there may be translation issues.
www.pixiv.net 
kk.now.cc
onob.gumroad.com 
