Once you have installed the plugin, you can access BuddyPress Contact form settings from Dashboard->Settings->User Contact Form as shown below.
Changing Tab slug:-
The option allows you to change the slug that appears after user profile to access the form. For example if it is ‘contact-me’ and then an example form url will be http://example.com/members/admin/contact-me/ for the user ‘admin’.
Control who can be contacted by users.
With this option, you can control which users will have the ability to receive message. Only selected roles(or all members as you prefer) will have the ability to receive message.
Control if users can toggle their contact form.
With this option, you can control whether you want to let yours have the ability to enable/disable the contact form or not.
Email subject prefix and file attachment.
With this option, you can enable attachment with the message.
Admin email option:-
You can control if you want to receive a copy of user’s message and also on which email address.