online fitting
 

Is it possible to customize a bike online?
Does anyone provide such services?
I mean, I turn on the camera from home and someone can judge ...

No, I don't think so . . . OTOH, you can fill out an online bike calculator which will give you suitable frame dimensions. I always advise going by the effective top tube length rather than seat tube length or nominal size.
Calculator: https://www.competitivecyclist.com/S...ulatorBike.jsp
After you get the bike, you can fit it yourself. My bike fitting primer: https://www.bikeforums.net/21296948-post3.html