Photopea is similar to Photoshop, but it is free.
Photopea is an advanced image editor, which can work with both raster and vector graphics. You can use it for simple tasks, such as resizing images, as well as complex tasks, such as designing webpages, creating illustrations, processing photographs and more.
Photopea can be used by professionals. It has:
Layers - to split images into several parts
Layer masks - just generally useful
Blend modes - specifying, how layers "combine" with each other
Brush - there must be a way to change the color of pixels
Selections - choosing, which pixels of layer you want to edit
Procedural adjustments - changing brightness, hue, saturation, convolutions (blur, sharpening ...) etc.
It also open web and tells you about all its APIs and how it performs some tasks, as it does not only stop at Photoshop, but also can work on gimp, illustrator, sketch files, so you can dispense with installing Photoshop, illustrator and gimp, so it is the best and most powerful alternative A site that works on editing and modifying images.
If you've used Photoshop before, you'll feel at home.
Photopea's interface is almost identical to Photoshop and you'll be able to relate to the gray-black theme.
You will find the toolbar on the right and the Layers and History panel on the left. Moreover, the right panel can be fully customized through the window tab.
The only problem is that you will have to rearrange the windows as per your convenience with each new project.
Photopea website link:
The follwoing link teach you how to use Photopea step by step: