I didn’t use worksheets or workbooks for my kids when they learned to write the alphabet. I taught them initially by using colored sand and then by using whiteboards and sketchbooks. It is important to not force your child to write. Instead, encourage scribbling and doodling by exposing your child to materials and drawing tools and let them express themselves freely. While they draw, pay attention to what they can do- lines, dots, dashes, circles, squiggly lines, zig-zags, spirals, waves… Keep in mind that there are also developmental stages of drawing, so it also can not be forced! Here (HERE) is a great article on the different stages of drawing. My biggest tip is to let your child thoroughly enjoy each step and try not to rush them.
When your child can more or less draw these lines and shapes, you can add in some fun drawings that incorporate the letters of the alphabet!
Many people have asked whether I taught my kids to write the uppercase or lowercase first. I started with uppercase because the letters consist mostly of straight lines and large curves, which my boys can already “draw” from my observation of their doodling.
If you need ideas for “drawing” the alphabet, here are some that I have re-created. You can always add a plastic cover on them and use markers so you don’t have to keep re-printing.
Letters A-I
Letters H-P
Letters Q-Z
As with learning the letter sounds, here are a few posts that might be helpful:
Ms Claudia 
Hi Ms Claudia, may I know where do you purchase for your kids sketchbook? I found so far either they are too big or too small. Thanks