Most restaurants of Maspalomas are on the application called Glovo. A few of them are also on Uber Eats. You can download those apps from the Apple App Store or Google Play Store. (Deliveroo and Just Eat do not operate in Maspalomas at this time).
Make sure you check your app for the time arrival of your food and come pick it up at the main entrance of your building as soon as your delivery guy arrives.
If you make them come directly to your own door inside your complex or if you make them wait, you should tip them. At least 1 or 2 EUR minimum. (the delivery fee does not include the extra time of searching you in your building. Especially if it´s too far inside or complicated or that they have to walk up the stairs) Also make sure you indicate the name of your hotel/resort/building in your address as this is how they can quickly identify your location.
Last but not least, delivery guys prefer when you have already paid your order through the app with your credit card. If you still chose to pay cash, please use the bill the closest to the amount to be paid as they carry a limited amount of change. (Example if your order is 8.35 EUR, do not give them a 50 EUR bill but a 10 EUR one and let them keep that change)