the following document is good as a starting point on how to manage your logs
https://www.strongdm.com/blog/log-management-best-practices
then as a strategy
if you want to go with a file you can choose JSON as a destination point since it is far more easy to parse and manage that kind of file
then
Use Azure Log Analytics, a part of Azure Monitor, to aggregate logs from different sources.
Create a Log Analytics workspace if you don’t already have one, and configure it to collect the necessary logs.