I’m trying to share the WiFi password with my mom and it won’t work

Before you begin

• On both devices, turn Wi-Fi and Bluetooth on; if either of you have Personal Hotspot on, turn it off.
• Make sure your Apple ID is added to the other person's Contacts app.
• Keep the other person's device nearby, within Bluetooth and Wi-Fi range.

Share your Wi-Fi password

1. Make sure your device (the one sharing the password) is unlocked and connected to the Wi-Fi network.
2. Select the Wi-Fi network on your friend or family member's device (the device you want to connect).
3. On your device, tap Share Password, then tap Done.

Share your Wi-Fi password from your iPhone, iPad, or iPod touch ...

https://support.apple.com/en-us/HT209368