Can i safely do backup on mysql version 5.5.62 and restore on 5.7.32 using xtrabackup?
This is not advised. If you consider the fact that a full backup using Percona XtraBackup is basically a snapshot of a live, running instance, the preparation of that backup is effectively running InnoDB crash recovery. Oracle requires that major upgrades go through each major version. So, you should first prepare the backup on to and for the most recent version of MySQL 5.5 first, ensure that the instance and data looks good, then follow the upgrade instructions for MySQL 5.5 -> MySQL 5.6, re-verify, and again follow the upgrade instructions for MySQL 5.6 -> MySQL 5.7, re-verify. For ultimate safety, this should all be done on a new server instance, leaving your original 5.5 alone just in case something fails along the way.
George O. Lorch III
Director of Server Engineering, Percona Server for MySQL, Percona XtraDB Cluster, and Percona XtraBackup