Philemon 1
1 Paul, a prisoner of Christ Jesus, and Timothy our brother,

To Philemon our beloved friend and fellow laborer, 2 to [a]the beloved Apphia, Archippus our fellow soldier, and to the church in your house:

3 Grace to you and peace from God our Father and the Lord Jesus Christ.

So this is to our home church!!
From my bible commentary:
The Jews had their synagogues, but Christians met in the homes of their members. The Christians of a city would be gathered into different “house churches” with a city “bishop” overseeing the different house churches.