Photo Collage Software

Any suggestions for software I can use to make collages out of existing photos on my laptop?
I have a mix of photos taken on cameras and my phone. I upload my photos to Photobox for printing as 6x4s, but sometimes I would like a couple of 3x4s instead of 6x4s.

I use this one

https://www.photocollage.com/

my mum uses one called picollage which seems good too

Thanks Maria, I've had a quick play with photocollage - looks promising.