Transmission of R factor is by -
Conjugation
Transduction
Transformation
Lysogenic conversion
Conjugation

Bacterial conjugation is the transfer of genetic material between bacteria through direct cell to cell contact or through a bridge- like the connection between two cells.
Conjugation is a process whereby a donor (male) bacterium makes physical contact with a recipient (female) bacterium.
Donor status is determined by the presence of plasmid.
This plasmid codes for specialized fimbria (sex pilus) and for self-transfer.
Sex pilus (conjugation tube) helps in the transfer of genetic material from male bacterium to female bacterium.
The plasmid is known as transfer factor (sex factor or fertility factor).
The plasmid may be R factor, which codes for transferrable multiple drug resistance.
The DNA of the plasmid replicates during transfer so that each bacterium receives a copy → Recipient becomes a donor and the donor retains its donor status.