On Debian Buster the file to edit is:

/usr/share/modsecurity-crs/rules/REQUEST-901-INITIALIZATION.conf

search for: setvar:'tx.allowed_methods=

roughly line 163... edit the line so that it includes the methods you need accept eg:

setvar:'tx.allowed_methods=DELETE GET HEAD POST PUT OPTIONS'"

save the file then restart apache: service apache2 restart

acn you are done!

On Debian Buster the file to edit is:

/usr/share/modsecurity-crs/rules/REQUEST-901-INITIALIZATION.conf

Search for: setvar:'tx.allowed_methods=

At roughly line 163, edit the line so that it includes the methods you need to accept eg:

setvar:'tx.allowed_methods=DELETE GET HEAD POST PUT OPTIONS'"

save the file then restart apache:

service apache2 restart