About the registration form
I have a small online store selling items that are not for everyday use. That is, just the one where registration is absolutely necessary, but most likely, the user will use it once. In this case, the registration form takes the form:

The “I'm not a robot” checkbox serves as a captcha, but you can argue about its relevance. After clicking on the button, javascript checks the correctness of entering the mail address and the state of the checkbox; if successful, the data is sent by ajax to the server, where it is checked again. If the mailing address is entered correctly and has not yet been registered, a new account is created, a password is generated, which is sent to the user's mail, and the new user is authorized. Thus, both parties win - the visitor is spared the torment of registration, and the site gets a more loyal user.
But the online store is not enough to know only the email address of the buyer. To deliver the goods, you will also need the client's address, phone number and, finally, a name. These data are obtained directly at the time of order:

And of course, the user can change his password in the profile by specifying the password generated during registration (for which he will need to check the mail, actually confirm it), and the delivery information will not have to be specified a second time.
UPD: Thanks for the comments. There are no more checkboxes)
UPD2: Logical sequel: about captcha