Shaikh Muhammad Baazmool (may Allaah preserve him) says: There is no specified number of rak’ats to pray on jum’ah day (i.e. specified number of Rak’ats after one enters the masjid and before the khutbah), rather what is established is that the number of rak’ats is unrestricted due to the Hadeeth reported by Imaam Muslim (rahimahullaah) in Sahih Muslim- that whoever takes a bath on the day of jum’ah and prays what is decreed for him (i.e. before khutbah begins), keeps quiet until the khutbah finishes, and prays (i.e. with the Imaam), he will be forgiven (i.e. minor sins) from that day of jum’ah to the next Jum’ah….[Ref 1]

After Jum’ah prayer, one prays either two rak’ats [Ref2] or four Rak’ats [Ref 3]

[Ref 1: For further details, see texts of hadeeth in Sahih Muslim Number 857 and the speech of Sh Muhammad Baazmool in [    بغية المتطوع page 121 onwards]

[Ref 2: Hadeeth in Sunan Abu Dawud Number 1/70 & declared authentic by Imaam Albaani (rahimahullaah)]

[Ref 3: Hadeeth reported by Imaam Muslim Number 881]