you are getting hired, you need to sign lots paperwork. If the company has the infrastructure to monitor its employee, it should be specified clearly in the employee handbook and you need to read it, agree and then sign.
Typically large corporation has security product in place. All the http and https traffic go through a transparent proxy server. All the URL will be logged, and typically it is deleted after a few months, otherwise the company has to pay extra fee for the storage in the cloud.
So if you have concerns, ask the engineer in you IT department, they will tell you what is monitored.