Is it permissible to begin a sermon with "Al-Hamdalah" (Praise be to God) and writing with "Al-Basmalah" (In the name of God), and with what should each conclude, along with mentioning the evidence?

It is from the Sunnah to begin sermons with praise to Allah, and to conclude the Friday sermon with seeking forgiveness. As for writing, it is from the Sunnah to begin it with the Basmalah (Bismillah ar-Rahman ar-Rahim), and there is no narration indicating that it should be concluded with specific phrases; rather, the conclusion should be appropriate for the context.