PITR is the ability to recover a database to a particular state at some time in the past - ideally to as near to when a failure started to occur as possible - usual scenario. You may want to have a view of the state of the db at certain times in the past, but there are better ways of doing this than performing (time consuming) restores from backups and logs!
Various systems have various ways (and names) for doing this.
Oracle has redo logs - your system crashes, so you go to your most recent backup and apply the redo logs to the point where they are still valid - ideally merely seconds before any failure. Ideally, your redo logs are not kept on the DB server but copied out to redundant storage somewhere - even off site.
Oracle also has the concept of Flashback queries where you can query the database as if it were some time in the past (also known as "AS OF" or "ASOF" queries - Oracle also calls it "Total Recall") when your system hasn't gone down, but for some reason you wish to know the state of play at some time in the past - there is considerable overhead associated with this, so care is required in making use of this feature.
SQL Server calls it Point In Time Restore (1, 2), but does not have Flashback queries, but does have snapshots. However it also has features which allow the user to do more or less the same thing using what Microsoft call (System Versioned) Temporal Tables - these permit "AS OF" queries as explained here - see this answer for more details. See also this answer in the same thread re. Change Data Capture and Change Tracking (more lightweight)!
An interesting take on this Flashback/ASOF query is to be found in the Datomic system - an immutable database (seemingly a contradiction in terms) - check out "asof" and "since" here.
There are two key concepts in recovery.
RPO - Recovery Point Objective: how many hours/minutes of data loss is acceptable?
RTO - Recovery Time Objective: how much time will it take to recover after business process interruptions?
A good explanation of these two ideas is to be found here. But, ye get nuttin for nuttin! The more stringent your requirements, the more money you're going to have to shell out for equipment and software!