Got an error

I used caps and a dash like SSDD22_ got the error “Warning: Cannot modify header information – headers already sent by (output started at /home/site/public_html/wp-admin/includes/template.php:1642) in /home/site/public_html/wp-content/plugins/db-prefix-change/dbprefix_admin.php on line 49

Will this change all new prefixes when plugins are added btw?

https://www.ads-software.com/extend/plugins/db-prefix-change/