Just like you can't do kindness or honesty. You are kind and you are honest. You can't simply check a box for kindness or honesty; it's part of who you are. We must think of accessibility in the same way.
You create an accessible modal dialog and use visible labels for your forms. You add alternative text to your images and you respect your users' reduce motion preferences for animations.
You avoid using flashing and blinking effects and you give each link a unique and descriptive text.
You add synchronised captions to your videos and you test your product with a screen reader.
You set up a process to handle accessibility-related user feedback.
You do all this because you want everyone to be able to use your product.
But just because you do all these things, doesn't mean you do accessibility.
Accessibility isn't something that you do. It's something that you are.