Problem
You want to reduce the number of digits in job and project numbers.
Solution
Changing Job and Project Number Length
Go to Settings > Your Account > Feature Configurations.
Using the search bar on the Feature Configurations screen, search for "seed". This will bring up the Project Number Seed, Job Number Seed, and Purchase Order Seed configurations.
Click Request Change on any of the options you wish to change.
In the window that opens, enter your PIN to the Pin number field. In the message box, enter a brief message and include the number you would like to start the numbering from.
Wait for the change to take effect.
Note: This change will only affect future job and project numbers. Existing numbers will not change.
Remember, this process does not apply to opportunity and estimate numbers. For those, consider suggesting a feature request in the ServiceTitan community.