How to install Google Tag Manager on your website?
Google Tag Manager is a great way to boost your website’s SEO, as it will give you a chance to create or/and update the existing tags for tracking the conversion, analyzing the website traffic, and much more.
Without editing the code you will be able to manage tags on your website, including Google Analytics, Google Ads, Facebook Ads, Floodlight, and the other third-party tags.
1. Open the Google Tag Manager Website
If you have not registered yet, you will need to create an account. In order to do this, simply click on the corresponding button.
It is better to have one account for one company.
2. Create an account
In this step, you will need to fill in your company name and its country.
As soon as it is done, you will need to set up the Container. For this, type in your container name, for example, it can be your domain. Then choose the platform you are targeting and finally click Create and confirm the Terms of Service agreement. 
3. Install Google Tag Manager on your website.
After the account and container are created, you will need to insert the provided code onto every page of your website. 
To do this:
1. Open your WordPress Dashboard.
2. Go to Appearance and then to Theme File Editor.
3. Locate the header.php file on the right sidebar.
After you located the file, press on it and add the codes from the Google Tag Manager into the <head> and <body> sections accordingly.
Here we are! Click on “Update File” button and enjoy the activated Google Tag Manager features.
There is an option to use different plugins for the Google Tag Manager installation, however, it is not really necessary, as it is really easy to manually install the Tag Manager. And the more plugins you have, the more there are potential issues with them.