Yes it is. The same way you comment here, just look for the comment box above the comments section and login before commenting.

I didn’t completely catch your question. But if you are talking about blockquoting, you can do it even in mobile. Something like this?

Welcome to fan posts!! Hope you enjoy it as much as we do! 🙂

It can be done by typing *lesser than sign* blockquote *greater than sign*. Then if you want to end the blockquotation, use *lesser than sign* *slash* blockquote *greater than sign*. I hope this is the answer to your question xDD