vi /etc/dhcpcd.conf
...
# Example static IP configuration:
#interface eth0
interface wlan0
static ip_address=192.168.150.191/24
#static ip6_address=fd51:42f8:caae:d92e::ff/64
static routers=192.168.150.1
static domain_name_servers=192.168.150.1
...

vi /etc/wpa_supplicant/wpa_supplicant.conf
...
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=DE

network={
        ssid="SSID-Name_1"
        psk="Password_for_SSID-Name_1"
        id_str="id_string_for_SSID-Name_1"
}

network={
        ssid="SSID-Name_2"
        psk="Password_for_SSID-Name_2"
        id_str="id_string_for_SSID-Name_2"
}
...