Ipaddr

Position of the interface configuration files:

/etc/sysconfig/network-scripts

ip addr

shows the names of available interfaces:

enp0s3: <BROADCAST-MULTICAST-UP-LOWER_UP> mtu 1500 qdisc
pfifo_fast state UP qlen 1000
link/ether 08:00:27:66:c7:99 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.40/24 brd 192.168.0.255 scope global enp0s3
valid_lft forever preferred_lft forever
inet6 fe80::a00:27ff:fe66:c799/64 scope link
valid_lft forever preferred_lft forever

Now the config file ifcfg-enp0s3 can be edited with the static config:

TYPE="Ethernet"
NAME="enp0s3"
ONBOOT="yes"
IPADDR="192.168.0.40"  
BOOTPROTO="static" 
GATEWAY="192.168.0.1"