While teams and players have very good representative ratings, from research and conversations with beta testers, you likely want to edit the names of the teams and players. Edits are saved in a separate file, which is then used to update all existing and new leagues. This means that your edits are immediately visible, and that they’ll be used if you create new leagues. Sharing names files will be simple on the desktop version, but I’ll also look into Steam Workshop to see if I can make it easier.
The behavior is a little different for career play. In non-career, you can have exhibition and single season games. Your edits are immediately applied to any saved games you have, and also to your current season. So if you’re in week 5 and decide to change the name of the Seattle team’s QB, the changes will appear in any saved games, in the season leaders, and in Seattle’s stats. In addition, if you create a new season, your edits will be used on the new season.
However, career play has the added complexity of new players coming in each year, so you actually edit different files based on whether you’re editing the 2015 season or a future season. Just like non-career, any edits to the 2015 file will apply to the 2015 teams and players AND will be used if you create a new career later.
Now, if you want to edit the names of players you drafted in 2018, you certainly can, and those changes will last from 2018 on! Of course, if you start a new career, those names will vanish.
One note – if you back up your career in 2017, make edits in 2019, and then reload your 2017 backup, you’ll be back with the 2017 names as well.