Tool Table Length and XY Offsets are applied with GCode Commands G43 Hn where n is the Slot or ID of the Tool Length/Offset to be applied.
G49 will turn off any Tool Length/Offset compensation.
Note a common mistake is to assume that changing Tools with an M6 Tn will automatically apply the Length/Offsets for then newly loaded Tool. GCode was designed in this manner to allow the operator full control of if/when the compensation for any Tool is actually placed into effect or removed.
A related issue and common source of confusion is with regard to Zeroing or Setting the DRO's. When Zeroing or Setting the DRO's the result is that a GCode Offset is modified to achieve the desired result. Its important to realize that the computed offsets will be dependent on whether Tool Length/Offset Compensation is currently in effect or not and for which Tool. Depending on your work process you may or may not want Length/Offset Compensation Enabled when Zeroing or Setting a DRO.
KMotionCNC has a Tool Setup Option to automatically perform a G43 Hn whenever a Tool is changed Manually with the on-screen Drop Down Selection. See here for more info.