Do i need to buy anything else to install a SATA 2.5inch SSD

As @ThatVietGuy says, you'll need SATA power (from PSU) and a SATA data cable. If you built the PC yourself, you should have got at least a couple of SATA (data) cables in with the motherboard.

The only other thing you want to check is whether your case has any mounts for a 2.5" drive. Standard desktop hard drives are 3.5", and basically every case will have mounts for a few of those. Most newer cases will have at least a couple of 2.5" drive bays too, but you probably want to check. SSDs are really light so even if you don't have any 2.5" bays you can always ghetto it with a zip tie or something, but if you want to secure it properly you can get a mounting adapter like this: https://www.amazon.co.uk/TRIXES-Mounting-Adapter-Bracket-Holder/dp/B00HFSMHDI/ref=sr_1_4?s=computers&ie=UTF8

BTW - both respones are assuming this is for a desktop. For a laptop with a spare 2.5" bay, you shouldn't need anything as the power, data and screws should all be there already.