You can leave the username as it comes, i.e. pi. However, I will obviously change the password. This can be done with the command passwd.
passwd
Raspberry Pi: Default Password & How To Changearrow-up-right, shellhacks.com, May 7th 2020
Use the system tool raspi-config to edit the hostname.
raspi-config
How to Change Your Raspberry Pi's Hostnamearrow-up-right, tomshardware.com, May 1st 2020
Last updated 4 years ago