Purchase orders for a partner can be created automatically or manually.
This setting, as well as more options, can be set generally in the Finance selection of the settings section.
These settings are copied into a new partner on partner creation.
In the partner settings, you can divert from these copied purchase order settings. These settings can be found in the financial tab of the partner settings pop-up.
If you choose to purchase order manually, you can do this for one, more or all accounts from the purchase order sections of the financial section.
You can choose to create a proforma purchase order to first check the purchase order, and only after you proofed the purchase order(s) finalize them.
NB: Once you accepted \ finalized a purchase order this purchase order cannot be rolled back!
A pdf will be generated for both a proforma and final purchase order.
If you want to adapt your company settings, partner settings (like the address or email) etc you can always choose to regenerate the purchase order with the new settings, by selecting regenerate.
To find partners with nonstandard purchase order settings you can use the report