Location to fill transmission fluid?

Sure here is how to check the transmission fluid level:

STANDARD PROCEDURE - CHECK OIL LEVEL

To properly check and fill the transmission, perform the following procedure:

WARNING:
There is a risk of accident from vehicle moving when the engine is running. Secure vehicle to prevent it from moving. There is a risk of injury from contusions and burns if you insert your hands into the engine when it is running. Do not touch hot or rotating parts. Wear properly fitted work clothes.

CAUTION:
A unique transmission fluid has been developed for this transmission. This fluid is NOT compatible with ATF+4 or any other current Chrysler transmission fluid. For specifics about this unique fluid see FLUIDS, LUBRICANTS AND GENUINE PARTS.

NOTE: Oil dye is not required to find leaks in the 8HP transmission. The oil dye can cause shift quality issues and is not recommended. The 8HP fluid has luminance that is visible under a black light.

NOTE: During this procedure, if an extended drain time has passed, (example: Valve Body was removed and the transmission fluid drained for an extended period of time.). Fill the transmission until the fluid runs out the fill hole. Temporarily install the fill plug. Lower the vehicle, start the engine, raise the vehicle again, recheck and fill the transmission, with the engine running, before lowering the vehicle and performing the transmission engagements and gear changes described later in the procedure. This needs to be done because it is possible that the fluid level could be low enough to cause fluid starvation during run up and internal damage could result.

NOTE: If the transmission oil cooler lines were replaced or drained it will be necessary to operate the transmission to get the oil temperature above 90C (194°F) to open the thermal bypass valve in order to get fluid to flow through the lines and ensure transmission is completely full. It will then be necessary to reduce the fluid temperature to between 30°C (86°F) and 50°C (122°F), in order to make sure the fluid level is correct.
Raise and support the vehicle on a level hoist (Refer to 04 - Vehicle Quick Reference/Hoisting - Standard Procedure) .
AWD vehicles only: If necessary, remove the front driveshaft (Refer to 03 - Differential and

Driveline/Driveshaft/Removal) .
AWD vehicles only: Using a scan tool, enable Emissions Rolls Test Mode in the PCM.
Start the engine. The engine must continue to run for the entire test.
Using a scan tool or the vehicle information center, verify that the transmission fluid temperature is below 30°C (86°F).
Disable the Electronic Stability Control (ESC).
Remove the fill plug from the right rear of the transmission case.
Add transmission fluid until it trickles from the fill opening.
Install the fill plug.

Lower the vehicle for access to inside of the vehicle, leaving the tires at least 8 inches off the ground.

With the brakes applied, place the transmission in Reverse and hold for 5 seconds.
Place the transmission in Drive and hold for 5 seconds.
Release the brakes, slowly accelerate to 2nd gear and hold for 5 seconds.
Apply the brakes and place the transmission in Neutral.
Raise the engine speed to 2000 RPM for 5 seconds.
Return the engine to idle and place the transmission in Park.

NOTE:
A full transmission will have fluid at the fill hole with the transmission between 30°C (86°F) and 50°C (122°F). Do not over fill.

Remove the fill plug and allow excess fluid to drain from fill hole or add fluid as necessary.
Install the fill plug.

AWD vehicles only: If removed, install the front driveshaft (Refer to 03 - Differential and Driveline/Driveshaft/Installation) .
AWD vehicles only: Using a scan tool, disable Emissions Rolls Test Mode in the PCM.
Using a scan tool, clear any DTCs.

This guide can help as well

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

Check out the images (below). Let us know if you need anything else.