This is a detailed step-by-step video of how to change the Honda CVT transmission warmer filter in the engine bay, the trans filter inside the pan, and the fluid along with all the torque values. Even if you call most Honda dealerships, they will not tell you these cars take two transmission filters. Searching online, will give you the part number for just one of the two filters. Please find the part numbers and current pricing as of August of 2023 below.

These CVT transmissions have a much higher rate of failure if the fluid and these filters are not replaced every 30,000 miles.

Honda 25420-5LJ-003 Strainer Assembly (CVT) - 2015-2021 Honda $17.00
Honda 91308-5LJ-003 O-Ring (21.8X1.9) - 2015-2021 Honda $1.50
Honda 21814-RJ2-003 Gasket, Oil Pan - 2013-2021 Honda - $11
Honda 25450-P4V-013 Filter 1996-2022 Honda - $22
Honda 25565-5LJ-A01 O-Ring B, 2015-2022 Honda $4
Honda 25564-5LJ-A01 O-Ring A, 2015-2022 Honda $2.50
Transmission fluid drain plug crush washers for Honda Civic 10-pack on Amazon - $6
Honda (08200-HCF2) CVT Transmission Fluid $10 x 6 = $60
FloTool 10701 Spill Saver Multi-Purpose Funnel, Blue from Amazon $2.50
Approximately $130

I purchased the all the Honda parts and fluid from either https://www.hondapartsnow.com/ or https://www.hondaautomotiveparts.com/ (not sponsors). If you know of better pricing with genuine honda parts online, please share in the comments.
Tools and items used for this job are in the video.