Hi there and congratulations!
From the "business end", he will be wanting to ensure the legality of the marriage. Such as making sure the two of you are not immediately related; neither are currently married etc etc. He will most likely need birth certificates to verify this and to check "UK" status.
Also, if one of you is divorced, he may not be able to officiate - depends which denomination as each have their own rules/regulations around this.
He will be interested to find out if you truly are making your vows before God, or just need the Church for a pretty background to your wedding pictures.
Don't worry if you already co-habit - the church has moved on about expecting "purity"; but he may want you both to attend a couple of classes to ensure you are both fully aware of what a lifetime commitment actually means.
Other things he will want to know is, will you be needing the services of the choir (more £s), perhaps the bell-ringers (more £s); the organist (guess what more £s)... do you have any favourite hymns or readings etc etc. He may talk over his "house rules", such as confetti, photo's during the service, video footage etc.
Blimey, hope I haven't put you off with that lot; but going prepared may save hassle later!
Have fun
Kx