If it is an international divorce, meaning if your spouse left the country and went back home and you cant find them, you will need to show that you made many attempts and realistic efforts to contact the person regarding a divorce. Keep any emails, proof of mailing correspondence, phone bills showing you have tried calling them or their family trying to get in touch with them, any documentation from the spouse indicating they are leaving you, etc...
You then go to a lawyer to proceed with a divorce. The divorce papers will be sent to the last known address you have for your spouse, make sure they are sent via a courier service which will reflect they were received and signed for.
If the divorce papers are received and your spouse does not respond by signing and sending them back or if they are never received (tracking shows recipient was contacted but it was never picked up/delivered) and you have this proof, your lawyer will have you do up an affidavit explaining the circumstances of the breakdown of your relationship/spouse's leaving and can then go to the court to ask for a divorce in absentia on the basis of abandonment. If your explanation and proof of contact attempts is enough to satisfy the judge they can grant your divorce on the spot if they are so inclined.
They want to ensure that your spouse had a fair chance to respond to the divorce request.
Sometimes they will want you to go the extra mile and make additional attempts at notifying your spouse of the divorce proceedings for example by putting an ad in the local news paper where your spouse is though to be residing, a notice in the courthouse in their town/city, ect...And give you a specific length of time that it must be posted and a date that you can return to court if there is still no response, after which they should grant the divorce.
