2 formatting questions with Double Header theme

Hi

1. In my archives page iwordpress puts dashes in between the words, and Id like it to put underscores
so right now it will do this
https://www.pursepage.com/handbags/jessica-simpson-hangbags/

and I want it to do this instead
https://www.pursepage.com/handbags/jessica_simpson_hangbags/
Anyone know if its possible to change this?

2. also is there any way to hve the archive pages be static so I can put seperate titles on them and seperate meta tags?

It creates the seperate archive pages dynamically and I cant figure out how to customize them.