Tickets and passes for urban routes are topped-up in advance. You can buy the tickets and passes from CP ticket offices, vending machines or, in the case of Porto, at one of the 800 or so payshop agents.
Passengers must validate their tickets for the Lisbon and Porto urban routes before entering the restricted areas or starting their or risk being considered a passenger without a valid ticket. 
At stations with controlled access channels, validate the ticket or pass when passing through the respective channels. At stations without controlled-access channels, passengers must validate their ticket at the station.
Validation at the validators and/or access channels is simple:
hold the ticket to the validation point without moving it;

• wait for the green light to come on and the validation completed message to appear;
• on the Porto urban train network, Anda app users must hold their mobile phone 2 or 3 cm away from the validator until a green light comes on, then check if the ‘journey started’ notification appears on the screen, since it is not possible to validate the journey on the train with the Anda app.

If you need support, there is a help button on the Vending Machines in the station access channels (where they exist), which you can use whenever you need information.
Whenever there is no ticket office in operation at the boarding point and no means of validation, passengers must contact the ticket inspector immediately after boarding to validate the ticket, under penalty of a fine of a minimum of €120 and a maximum of €350 - Law 28/2006 of 4 July.
We are counting on your co-operation.