Yes you can add hops to the same FV. Pellets or whole hops are both fine but pellets are probably better in terms of giving up their goodness, gm for gm. If you are new to dry hopping I suggest you use a large nylon mesh bag to contain your hops to avoid them passing through at packaging. The weight of hops you add is down to experience, personal taste and the hop you are using. My suggestion for Citra is to go for 50g of pellets as a start point if you have not used them before.Also can I dry hop at the end of the fermentation in the same FV if so any ideas how many hops to add to a 23 litre batch
Also is it better to buy the pellet or leaf hops
I’m also experimenting with a Wilko Cerveza & added Clarity Ferm to clear out the Gluten after 14 days fermenting still seems very cloudy
More here
https://www.thehomebrewforum.co.uk/threads/a-newbies-guide-to-dry-hopping-your-beer.61045/
And be aware that dry hopping is more about aroma compared to hop tea infusions which are more about flavour. If I make up a hop tea I use 100ml water @ 80*C for every 10g of pellets and allow to cool slowly then chuck the lot in, to get the best of both worlds.