Are there any mandatory prayers in Christianity? Does Bible impose any type of mandatory prayer that you have to offer at particular time or particular day? If so, what are some important prayers? Is a prayer at Church more worthy than a prayer at home?
The closest would be the model prayer given in Matthew chapter 6 as part of the Sermon on the Mount. This prayer is understood by most to be an example, or model, rather than something to be repeated verbatim. 

So, no, there are no specific mandatory prayers given in scripture, other than that we are to pray &mdash; and to pray without ceasing. Mandatory prayers reflect an ethos that is more about rule keeping. While there are rules, Christianity is not really about rule keeping: it's about building a relationship with God, and by extension your fellow man.