Mod_rewrite via htaccess?

[nakins]

I'm on 1and1 and I have an app that requires mod_rewrite, which isn't enabled on the server. However, 1and1 support says I can enable it (I assume by htaccess), but they don't tell me how, but rather provide me with a few links from a Google search. My question, how can i enable mod_rewrite via htaccess? What do I need to put in there? If mod_rewrite was enabled on the server, would there be a "default" config, or default statement or directives, whatever?

Thanks

[YAOMK]

in .htaccess:

RewriteEngine On

Some web hosts will require you enable the rewrite engine through a local php.ini instead.