There's no need to create custom button. You can use Multi Paged Form

ok, thank you. i see Multi Paged Form is available in enterprise only. I am using community edition.

My requirement is to create a multi paged form in wizard mode, collect data from user in the wizard and send all the info to external API, not store anything in database. No need of DB tables also for this multi paged form fields.

Is it possible to do this in community edition?

With Multi Paged Form you can't make wizard type "screens" as we understand them in the traditional way. For each page form you have to use the "Save" button. You can't use a global save button for example at the end of the wizard to save them en masse.

You also can't create dynamic routes in form navigation. For example, going from one form to another (from 1 to 3) based on a value in one of its fields and not necessarily to the next numerically (from 1 to 2). And even if this feature existed, you would still be able to access a form even if it was outside the route, and this is not safe.