Website link field - to allow entry that will auto link

Single site.
Events +

Site aims to allow many end users to put up events..
Most of these users are not web savvy..
Need to create 2 custom fields which allow simple text entry by user to achieve.

So setup as Tax - or fields and how to autolink so user does not interfere with html etc?

Display in Events..
Website - which will automatically link to their website if entered..
Phone numbers - which will automatically achieve click to call if mobile..