You can look at the backup tables in MSDB, backupset. There's a lot of information there on the type of backup, when it occurred, if it was successful, etc. However, that's not going to tell you what the intention of the backup was, how often it's supposed to be run, or anything else. That information should be in the code in your Agent jobs, 3rd party tool, what have you. Further, somewhere there should be an Service Level Agreement (SLA) document with the business that defines Recovery Point Objectives (RPO) and Recovery Time Objectives (RTO). Combining the RPO, RTO, and the code will tell you what the backup strategies are. The information from MSDB will help you identify if the backup strategies are working to meet the SLA.