Each country has different provisions regarding the longest period of time to stay in Turkey. Whether it is using a visa or visa exemption.
It can be 30, 60, or 90 days. For example, take it 90 days. Then you can stay in Turkey for 90 consecutive days. Or you can also do it separately but still within 180 days from the day you issued the visa or used Visa exemption.
If foreign visitors want to stay longer than in Turkey, they are required to apply for residence permit.
It must be done before their visa or visa exemption expires, or they will be asked to leave the country.
First Time Application
It you never apply for residence permit before; you need to lodge to Directorate General of Migration (Göç idaresi) online website to stay longer legally in Turkey.
After you enter the website, choose the e-Residence. It will lead you to E-Ikamet Residence Permit Application. There, input any document required.
In order to make an appointment date to come to Turkey iResidence (Foreign Residence Services Office), you need to input a Turkish local address. The province will determine which office you must attend.
Do not cancel the active application before the due date, or it will not be processed and considered as a violation. However, the appointment date and the processing time vary between one to another.
But how if I missed the appointment date?
Nothing will happen. Just make a new appointment. There is no direct penalty for missing the appointment.
But you should carefully check the rebooked appointment date against the expiry valid date of your visa/visa exemption.
Because the real problem is,
your appointment date exceeds the visa expiration date. When it is over 15 days after the expiry date, you will carry a re-entry ban and technically been illegal to stay in Turkey.
So, watch out and try to avoid it.
Foreign nationals that already have residence permit is required to have it extended if they want to stay longer in Turkey. For extending the permit, they also obliged to have a private health insurance.
Application of the extension could be made within 60 days prior to its expiration. If you try to apply it before those time (such as 3 months beforehand), it will not be accepted.
You are required to apply the renewal/extension residence permit through the e-residence system. There, fill the application and provide the requirement document.
After it is complete, send them to the related Provincial Immigration Administration Office (Göç İdaresi) in your current province by mail within 5 business days.
Please remember to not overstay with the expired residence permit. It is considered as an Illegal stay and a violation to the Turkish Law. You would be fined and receive a ban for entering Turkey.