Canon EOS Rebel SL3 DSLR Camera with 18-55mm Lens (Black) - Manual (Page 278)

278
HDMI Output Resolution
Set the image output resolution used when the camera is connected to a
television or external recording device with an HDMI cable.
1
Select [HDMI resolution].
z Under the [ 5 ] tab, select [HDMI
resolution] , then press < 0 >.
2
Select an item.
z Press the < W > < X > keys to select the
item, then press < 0 >.
z Auto
The images will automatically be displayed at the optimum resolution
matching the connected TV set.
z 1080p
Output at 1080p resolution. Select if you prefer to avoid display or delay
issues when the camera switches resolution.