This is a template to make 1.18 texture packs off of.
How to: Download the zip. Open it and look for the textures you want to edit. Open the textures in a photo editing software. I use Photoshop, but anything will work great. Once you have edited the texture save as a .png and replace the one you made with the default one. MAKE SURE IT HAS THE EXACT SAME NAME
Editing the Resorce Pack GUI
How to: In this folder there are two other items besides the assets folder (where you textures live) The first is pack.mcmeta this is where you can edit the name that will show up in the resource pack GUI The second is pack.png this is where you pack.png or the logo of you texture that will be shown in the GUI lives. You can make this anything you want as long as it's 128x128px
Hope you make some great textures! I would love to see them! Just pull from this repository and I will look. Cheers!