WHERE is lock transparent pixels

I use photoshop on desktop frequently and just downloaded it on my ipad, and it seems theres NO lock transparency? How is it that i can lock the layer normally, and have lock transparent pixels work when i do it on pc and load the file, And that theres lock transparency in fresco but i cant on ipad photoshop?:/ Am i just missing it or is there really no option for this cause clipping mask is annoying at best for my workflow and i'd rather not use it for this purpose