Some time (two words) means a period of time:
▶️ It took me some time to fix the computer; it had a number of problems.
▶️ I spend some time listening to English every day.
▶️ Sarah worked at that company for quite some time.
(quite some time = a long time)
Sometime (one word) refers to an unspecified time, usually in the future, although
it can be in the past as well, as in the third example:
▶️ Let’s get together for lunch sometime.
▶️ I’ll call you sometime this afternoon.
▶️ I don’t remember exactly when I bought this shirt, but it was sometime in the
past year.
Sometimes means occasionally:
▶️ Usually I wake up early, but sometimes I sleep late.
▶️ Sometimes we have to work on Saturdays, if there’s a special event.
▶️ While reading this text, I sometimes had to look a word up in the dictionary.