Easy webdav server

My boss just asked me to setup a way for him and the other employees to securely access the network drives from anywhere - oh and it has to be done for free (or at least for very very cheap).

I’m kinda their goto guy for all techy things and I’ve never set up a server but it seems to me that a simple ubuntu server with webdav set up would be the easiest and best solution? Today I’ve been looking into various how-to’s but I’m still not sure what the best route to take would be.

Any advice would be really helpful.

Thanks.