how anyone can become mod of a specific board?
Anyhow person cannot be a moderator, know this and have peace, you must have proved yourself approved to deserve such a position with what you have rone in the past to the forum's development and what you can offer in the future time to come, there's a lot to be required of you because you have to be an active member with year of accurate understanding of how the forum works, when there's a need for a moderator, the admin will announce it out and those qualified will apply.
what mod does when they become mod
They ban users, delete posts, move topics, lock threads and unban users as the case may be.
and how the interface on this forum look like after becoming mod?
How can i know this when am never a mod, maybe the mods could tive a reply on that
do mod get paid? who pays to mods and how much they earn?
Wait until you become one before you can know how much they get paid and permit me to say this that you're too inquisitive with unnecessary questions.