If the company takes out a loan from the bank or a third party loan provider, then the transaction should go in here. The category represents the total amount you owe to that party.
Loans from other providers such as Funding Circle.
What's not included
Director loans/transactions should be dealt with through the relevant director loan category (Loan to Director or Loan from Director)
Loans to employees should be categorised in to the employee benefits section of Ember.
HMRC regarding business loans here.