Regarding the update of the custom field in salesforce apex language

I need some suggestions for the code which overrides the custom field which already stored as record in object. I have created one object signup with some fields like mail id, password and confirm password with validation, then I have created page with those fields and I have save thos开发者_Python百科e details to the signup object.

Then I have created another page with mail id and new password, so here i am facing one problem that i am unable to update the new password with the password field in signup object.the password field in signup object should override with the new password.

If any suggestions with code is very helpful to me.

First off, keep in mind that storing passwords in salesforce is frowned upon, especially if you are an app builder (see here)

In order to update a field on the form you must first load it in the background, the simplest way is to use builtin standard controller features since that controller automatically loads all fields referenced in the visualforce page that uses it.