Newbie questions: Underscore necessary between words?

When I create a thing or field do I need an underscore between words? “Last_Name” or “Last Name”

or is that just a coder thing?

And if I haven’t done this for 20 fields, can I change them all now without messing things up? I noticed many things auto update throughout the workflow when I change a name (however changing the title of a web-page seems to mess things up)

Also can I put a question mark in a field name?

No, you do not.
And you can change field and thing names at any time.

I would advise against using punctuation in such names, however.

If you have a Boolean (yes/no), it may be tempting to add a question mark to the end, but it will just make your expressions look funny.

So, don’t have a field Onboarded? on the User object, for example. Call it Onboarding Complete.

Bubble doesn’t bug with any characters (as I know). I’m using always for Y/N a ? like Process_Completed? and I used (underscore) _User to indicate a link to another data table and underscore every variables between words (make do_search value easier to find).