Art Comission HELP PLZ

Hello, i am Zayne. I’m artist and Musician. Right now, i use FIVERR to sell my art and comissions stuff. I really want to remove the middle man and just sell directly from my Website. There are a few problems i am having though and i need ur thoughts please
1. I need people to be able to send directions of what they want when they checkout and me to receive it. I wanted to use a Form but idk if it is possible, maybe u know ?
2. I want people to be able to TIP ME. is there a way i can add that ? I want to start simple by selling 5$ drawing comissions all next year, i just really want to be able to get more if they are happy with how it comes out.
Please let me know anything, i rly want to sell custom art and comissions on my website but i want the user to feel like it’s a good experience. I care most about them being able to send instructions, and me being able to send them the final digital artpiece at the end. And maximizing how much money i can profit cause art and music is my entire life i don’t want to do anything besides that

Here is my site Read-Only: LINK
(how to share your site Read-Only link)