There is no data icon

If there is no data icon (G, E, 3G, H, H+, 4G, LTE, 4G+, LTE+, 4.5G, 5Ge, 5G, 5G+, 5G UC, etc), it may be for any of these reasons:

Refer to No service or Emergency calls only.

Simply enable mobile data. Tap and hold the top of the screen then move your finger down to extend a menu downwards. It may have to be pulled farther down. Ensure Mobile data is enabled.

The phone would most likely be able to set up data without it. If APN settings are not automatically set, you'll still need to enter APN settings, then save, then select your settings. "Name" - the phone requires it, and it is displayed on a list of selectable APN settings. "APN" - the phone requires it, carriers normally do not, it'll be sent to the carrier in an ESM Information message, the carrier need not necessarily use what you specified. "APN protocol" - Also sent in an ESM Information message. If APN settings are not set, the phone stays in the CONN(ECTED) state until disconnected due to inactivity. If causes are supported by the software, a Cause of 19 may be displayed if you substantially misconfigure APN settings.

It is possible to connect to your carrier over another carrier if both carriers agree. The phone may disallow data use while roaming by default. If so, and using data while roaming is intended, enable data use while roaming in the settings of the phone.

If the phone has a data limit set, and the limit is exceeded, the phone's ability to use mobile data will be deactivated until the limit is raised or the limit is deactivated.

These features might not be working for a variety of reasons. For example, ensure that your data plan is valid.

A tower may bar data services.

If you misconfigured this setting, the phone will only be able to log in for calls and similar services, not mobile data. Correct the misconfiguration if so.

Where applicable.