What does Numbers 6:21 mean?

These are the instructions for someone who takes a Nazirite vow, whether they're a man or a woman. If they want to give more than what's required, they can, but they have to follow all the rules for the Nazirite, including any extra promises they've made. Numbers 6:21 - Modern Text Bible

(This verse wraps up the Nazirite laws, making it clear that anyone—man or woman—can take this vow, and if they want to go above and beyond, that's fine, but they still have to stick to the basic rules.)