With our category system you can create custom rules to your categories. 

Therefore you can either go via 'Settings' > 'Categories & Rules' to the category (or add a new category) > 'Edit custom Rules' to edit or add a new rule

or

select the transaction from the list of your transactions > add a new category or select a  category from the list of categories > choose to create a rule for this category

or

select the transaction from the list of your transactions > add a new category or select a  category from the list of categories > tap on 'Create Rule from Transaction'

You can create the following rules: 

• Select the Condition for the Rule
• the following conditions are available: 
  • 'Transaction contains all items': 
    To match a transaction each item in this list has to appear in the transaction. Enter keywords separated by comma.
  • 'Transaction contains any item': 
    To match a transaction at least one item in this list has to appear in the transaction. Enter keywords separated by comma.
  • 'Transaction does not contain':
    To match a transaction none of the items in this list may to appear in the transaction. Enter keywords separated by comma.
  • 'Amount':
    Choose if the transaction should be incoming or outgoing in order to match this rule.
  • 'Accounts'
    Using this condition you can apply this rule for specific accounts only.
  • 'Low Priority':
    If more rules match with a transaction, the rule with 'Low Priority' will we executed last.

Keywords can be all elements like transfer reason, receiver, sender, IBAN etc.
You can add as many rules to a category as you want.