In this configuration activity we are able to define matchodes for searching in customer master data.
Transaction: OBB2
IMG Path: Financial Accounting (New) -> Accounts Receivable and Accounts Payable -> Customer Accounts -> Master Data -> Matchcodes -> Check Search Fields for (Customer) Matchcodes
Table: TFMC
After starting the transaction you will get notification that your settings are cross-client so you should be careful.
On the main screen you will probably have following if you did not do any changes so far.