1.8t coolant issue

got home from work this afternoon, pulled onto the drive and as I was looking out rear view mirror noticed a little white smoke coming out exhaust, didn't really think nothing of it, went inside and did a few bits, came back out about an hour later as it was playing on my mind, started the car up no smoke so I opened the bonnet and had a quick look around the bay couldn't see anything out of the ordinary until I heard the fan kick in and I looked and noticed the coolant level was below minimum level.
I can't see any obvious signs of it leaking.
Should I be concerned more so than I am at the moment?
I texted my friend who replaced my turbo and he said he had to top it up when he replaced the turbo which I'm puzzled by? And said to top it up and keep an eye on the level, and also to check the oil filler for any gunk as it could be the head gasket.

Anyway I went to get myself ready to go to eurocarparts for some coolant and realised they were shut, can i top up with just water? As I need the car for work and could really do with it not being off the road.

Any help/advise on this is, as always appreciated.
And apologies for the long post

Thanks for confirming that, wasn't sure if I was thinking right about just going to eurocarparts or halfords and picking up there gear. I just checked the docs that came with car and on the service history, the supposed last service was last July but looking closely they've changed the ****** date! May not be related but definitely need to get the oil changed

Topped up with water last night, level remains the same today after getting home from work. Engine seems to be running a lot better and startup is smoother. Will keep an eye on the level over the next few weeks and hope I just over reacted about it

No more problems with the coolant level other than not figuring out why it had got so low in the first place.

No I didn't, I have had it scanned and it tells me a sensor needs changing just not sure if it's too or bottom one. Still get same issue I've got used to it and react when I need to. Probably not the best way to treat the car.

Keeping an eye on the level top up if needed and constantly check to make sure there are no leaks or the ' Mayo' stuff. My temp gauge can be temperamental too and I have no reading on gauge so that could be a reason why it drinks it.

Many thanks for that! ^^^