Android offers users a whole range of customization options, some of which are useful for everyone, while others are intended for power users only. One of these lower level settings is the name of the access point ̵
The APN is something most users do not need to worry about. You can insert your SIM card into your phone, possibly reboot it, and connect to your carrier's network. You can make calls, send messages, browse memos, and other important things. However, if you are still playing around with custom ROMs or using an MVNO, you may find that things do not work automatically.
What is an access point name (APN)?
The APN is all the information your phone uses to connect to your operator's network. This list lists the address that your phone uses to connect to the network, the ports used to manage Multimedia Messaging Service (MMS) messages, the type of data that the APN uses, and other information to help ensure that it is connected that your phone is working properly.  Some settings – such as "APN Type" – can be optional and your phone will continue to work without being 100% correct. Others like "MMSC" and "APN" are more important and your phone will not work if they are not entered correctly.
Fortunately, most phones have the APN built-in for traditional carriers, so you'll need everything. Put your SIM card in and let your phone work its magic. This also applies to some prepaid carriers: I use Mint Mobile, which runs on the network of T-Mobile. When I insert my SIM into my Google Pixel 2 XL or my Samsung Galaxy S8, it just works. The phones already have the APN, and they know which one to load in order to connect to a specific network.
Adding or modifying your APN
If you need to change your APN settings for security reasons, this is easily possible. Start by opening the Settings app on your phone. The exact name of the menu varies. However, tap the menu that handles your network settings. On the Pixel 2 XL with Android 9.0 this is referred to as "Network & Internet". Then tap on "Mobile Network".
. Tap on "Advanced". "Scroll to the bottom of the menu and select" Access point names ".
Tap the three-point menu in the upper right corner. Then select "New APN".
Your APN settings may be included with your prepaid SIM card, or you may need to search for it. Enter the details exactly as they are listed. Then tap on the three-dot menu in the upper right corner and select "Save".
. You may also need to make changes to an existing APN. To make these changes, tap the APN you want to change. Tap each category and update the details as needed. Tap the three-dot menu and select "Save" when done.
. The preinstalled APNs are unlikely to be changed. When you open them to see the details, each item is greyed out. If you tap on them to change them, you do not have to change anything.
Once the If APN is set, you do not need to change it again unless you change the network operators or reset your phone to factory settings. Feel free to make phone calls, surf the internet and much more!