Edit the following file:

Sudo Nano /etc/iscsi/iscsid.conf

Remove the # from the following lines and update the username and password accordingly

node.session.auth.authmethod = CHAP
node.session.auth.username = username
node.session.auth.password = inboundpassword
discovery.sendtargets.auth.authmethod = CHAP
discovery.sendtargets.auth.username = username
discovery.sendtargets.auth.password = inboundpassword

Now you can run a discovery scan
iscsiadm -m discovery -t st -p ip:port
(example: iscsiadm -m discovery -t st -p 192.168.0.1:3260)

If successful you should get a response
192.168.0.1:3260,1 iqn.2010-03.com.example:test.vm

Now you can login to the target iqn
iscsiadm -m node -T target_iqn_name -p ipaddress -l
(example: iscsiadm -m node -T iqn.2010-03.com.example:test.vm -p 192.168.0.1 -l)

Here is if you want to login to all discovered LUNs
iscsiadm -m discovery -t st -l

The information is stored in the node database found in /var/lib/iscsi.

To log out of the target
iscsiadm -m node -T target_iqn_name -p ipaddress -u
(example: iscsiadm -m node -T iqn.2010-03.com.example:test.vm -p 192.168.0.1 -u)

Then remove from the database so on a reboot it does not reconnect
iscsiadm -m node -T target_iqn_name -p ip address --op delete
(example: iscsiadm -m node -T iqn.2010-03.com.example:test.vm -p 192.168.0.1 –op delete)

To logout of all targets
iscsiadm -m node -U all

References:
https://www.thegeekdiary.com/how-to-configure-iscsi-initiator-client-in-centos-rhel-7/

https://library.netapp.com/ecmdocs/ECMP1217221/html/GUID-826A3F69-420C-457B-AE35-91DFA7B3B7AB.html