Your internet service provider (ISP) gives you complete access to the internet, but they also keep tabs on you. Let's look at some secrets your ISP keeps from you.
Browsing History
Your ISP can see the full web address of any site you visit, especially if it isn't encrypted.
When you Google search, internet providers can't directly see what you search, but they can see what site you clicked on.
If you wanted to delete your browsing history, your ISP can still see it. Deleting browser history only deletes it from your phone or computer.
Your ISP still has the logs, and you can't delete their record of it.
Make sure every site you visit is using HTTPS. Most websites these days are, but you should always double check.
With HTTPS, your ISP can only see the domain name of the site, but not the specific page.

How ISPs Use Your Data
ISPs are supposed to collect data to understand their customers better. It helps them build faster services and troubleshoot issues. But they have other ideas in mind.
Your data is mainly used for advertising. Then ISPs make deals with data brokers to fine tune their ads - like ethnicity, income, and political affiliation.
In most countries, ISPs are legally required to monitor and record your browsing history and give it to the government if requested.
They are also legally obligated to hold your data for a period of time ranging from 90 days to 2 years.
You should consider using a private operating system that isn't Windows or macOS. Tails is a private OS based on the Tor network.
You can run it directly from a USB, so once you're done browsing, that data is wiped with each session.
VPNs Help, But...
An ISP can still block your VPN client.
Internet providers can block any IP addresses related to a VPN provider, or they can disable communication ports.
But doesn't mean you should give up. You can fix this by switching to different server, port, or protocol.
VPN clients like NordVPN have strong servers designed to bypass restrictions.
There are thousands of VPN servers in the world, you can't block them all!
Wrapping Up
Your browsing history is on full display, especially if you're visiting websites with HTTPS.
Your data is a target for advertisers and governments. Consider a strong VPN and private OS.
And even though VPNs can be blocked, that shouldn't discourage you from using them.
Change the port or protocol, or look for VPNs with obfuscated servers.