For GMRS, the usual offset (it’s not in the rules, but it is the common practice) is to transmit to the repeater 5.000 MHz above the frequency the repeater transmits on. The rules require that you transmit to a GMRS repeater on one of the eight 467 MHz Main Channels and that the repeater transmit on one of the 462 MHz Main Channels. To make things easy the programming for certified radios always uses a 5.000 MHz offset. So the pair you program in a radio that uses the repeater will receive on 462.675 MHz and transmit on 467.675 MHz. So the repeater must receive on the 467 frequency and must transmit on 462 MHz.
For a user radio you MUST program the correct transmit tone, in your case 123.0 Hz. Programming a receive tone is optional. Leaving it empty will allow you to hear everything on that frequency and might help you troubleshoot.
For the repeater you program both if that’s what you want. If you don’t program a receive tone on the repeater anyone will be able to activate it.
The 0.600 MHz offset is standard for VHF radios, such as 2 meter ham bands.
Welcome, @WRTQ263! One really nice feature of the forum is the ability to add people to your ignore list.