Most of the times, suppliers will send you invoices for the same ledger, e.g. a Letting company will mostly send you invoices for Letting fee. You can now set a default ledger to any supplier so when inserting new invoices, SleekTech will prefill the ledger based on the supplier default.
This is how to insert the default ledger when entering a new supplier:

You can also change the default ledger for an existing supplier:

Now when creating an expense for the supplier the default ledger will automatically be selected:

Want to know more? Click on following links.