1. Nearly all smartphones allow a second number - you need to get a sim card (which might be a V-SIM)

2. Delegates and second users are separate issues. - Delegates was what the discussion was about.

3. The phone biometric access is bound to one human - if that is the de facto personal ID only one is allowed.

4. Multiple User Accounts: Some Android phones allow you to create multiple user accounts, similar to a computer. Each user has their own apps, settings, and data. How to do it: Go to Settings > System > Multiple users (this path might vary slightly depending on your phone model). From there, you can add a new user.
5. Guest Mode: If you just need to temporarily share your phone, you can use Guest Mode. This provides a clean, temporary environment for the other person. How to do it: Swipe down from the top of the screen to open the Quick Settings panel, tap on your user icon, and select Add guest.
6. Family Sharing: On iPhones, you can use Family Sharing to share apps, music, and other content with family members. However, this doesn’t create separate user accounts on the phone itself. How to do it: Go to Settings > [your name] > Family Sharing and follow the instructions to add family members.
7. App-Specific Sharing: For specific apps like messaging or social media, you can often add multiple accounts within the app itself. How to do it: Open the app, go to its settings, and look for an option to add another account.

Unclear if we want to be creating a survival guide for the technology perplexed?  or just outlining the problems.