We are planning to migrate our firewall to Cisco meraki from cisco ASA. Could someone help me with the migration planning and also let me know is there any automated configuration migration tool in Meraki
Just ask if there is anything unclear in your planning.
IMO, the most important step is to document which services you use on the ASA and if these services are needed after migration. The MX is far less capable than the ASA in nearly everything up to Layer3/4. It can be sufficient, but I ended up very often to still have an ASA alongside with the MX.