not getting texts from androids

Text messages from non-iOS devices are SMS. They are controlled by your cellular carrier, and there is no setting on the iPhone that controls them. You need to contact your carrier to ensure that your account includes an SMS plan. It is possible that your carrier may need to reset yours, but there is nothing that you can do on the phone itself to change the sending/receiving of SMS.

"... there is nothing that you can do on the phone itself to change the sending/receiving of SMS."

Not quite true:

You MUST also verify that Settings, Cellular, Cellular Data is set ON...

If Cellular Data is not set ON, incoming SMS messages will NOT be received, and outgoing SMS messages will NOT be sent.

(iPhone SE, iOS 11.2.6)

Actually, SMS will send/receive, it is MMS that will not. SMS uses the cellular voice channel, but MMS uses cellular data, two different things. You do not have to have cellular data for SMS, just a compatible plan from your carrier.

Thanks for the correction.

Still trying to understand the OP's issue of not receiving messages from "Android" devices...

So isn't really an "Android" problem, just a matter which type of message is being sent by the Android device in use: SMS or MMS?

Your welcome. Generally when an iPhone user cannot receive SMS/MMS, it is a problem with their account provisioning at the provider. They may just need to get the account reset at the provider side. If you do not have an SMS/MMS plan as part of your cellular account, you would not receive SMS from the Android user. And it generally isn't whether it is SMS or MMS, it is about the account. However, if they do not have cellular data turned on, then they would not be able to receive MMS.