Invoke document picker with a button in form

Hi, i have a use case to invoke a document picker when i click a button in a html form which is present inside a channel. Is this possible to achieve?
If so how can i do that? Thanks!

Hi,

do you mean from within the channel manager?

yes, i have a channel inside the channel manager with only a html form in it. I want to open document picker when i click a custom button.