Abundant Salawat on Friday
اللَّهُمَّ صَلِّ عَلَىٰ مُحَمَّدٍ وَعَلَىٰ آلِ مُحَمَّدٍ
Allahumma salli 'ala Muhammadin wa 'ala ali Muhammad.
O Allah, send blessings upon Muhammad and upon the family of Muhammad.
What it means
The Prophet ﷺ asked us to send him many blessings on Fridays in particular and told us that our blessings are presented to him. The hadith commands abundance without fixing a number or a special wording, so any authentic form may be repeated; this short one is easy to say many times.
When and how
Repeat it throughout Friday, on the way to the masjid and while waiting for the khutbah. There is no fixed count in the sunnah, so set yourself a number you will actually keep.
Its virtue
The Prophet ﷺ said to increase blessings upon him on Friday, because the blessings of his ummah are presented to him, reported in Sunan Abi Dawud 1047.
Source
Abu Dawud 1047 (the command to send abundant blessings on Friday)