You can start by sketching your ideas on paper and then scanning them. Use free online graphic design software to add colors and details.
Well, you could come up with a story first. Then, draw the characters and scenes by hand, take pictures, and use simple photo editing apps to assemble them. Another option is to use online templates and customize them to your liking.
First, think of a unique concept. Then, try using basic shapes and lines to draft your comic digitally. There are also some free online platforms that offer basic drawing tools and guides to help you create without the need for specialized software.