Your Mac will automatically remember the Wi-Fi networks you were connected to in the past. However, the network that connects automatically may not be the best option. If you want your Mac to forget a Wi-Fi network, do the following.
In addition to removing old connections, forgetting a Wi-Fi network can solve connection problems. If a network has changed its password and your Mac doesn't give you a password prompt (or if it's just flaky), you can try forgetting the network and reconnecting it.
To do this, click on the Wi-Fi icon in the menu bar of your Mac on "Open network settings".
. Click here on "Advanced".
. Scroll through the Wi-Fi tab, select the network you want your Mac to forget, and then click the minus sign (-).
In At the command prompt, click "Remove" to forget the network. This also removes the network's credentials from your iCloud keychain, making them unavailable to all other Apple devices.
. Click OK on the Wi-Fi screen.
Click Apply in the network window to save your changes.
Your Mac has now forgotten the Wi-Fi network. If you want, you can click the WiFi icon in the menu bar to log in to the network again.
If you use multiple Wi-Fi networks in the same place (for example, at home or in the office), you may not want your Mac to forget one of them. In this case, you can prioritize those that you use most often.
CONNECTION: Prioritize Wi-Fi networks on a Mac