About 1040 schedule1 other income

I have an income that I would like to fill in the other income box (line8) of 1040 schedule1. I haven't received the corresponding tax form like 1099, so I don't know how I can use turbotax to put this income in that place. I've gone through all the processes and can't find an interface about what to fill in for schedule 1. Looking forward to answer.