How to attach hose to router table port?
Given that you've provided no information about what actual size the shop vac hose (there are multiple "standards" though 2-1/4 inch is the one I'd usually assume) or the size of the hole in the router fence, either something like this, or something like that in the the other direction (or a chunk of wood with an appropriate size hole drilled in it.) The first can be cut to provide various smaller sizes or a flange, the second increases size to 4 inches.

Shop vac adapter (or Shop vac hose adapter) will get results in a search engine.

Or 1/3 of a roll of duct tape... ;-)