No you can edit the templates from Appearance Editor, or via cPanel / FTP.
But these are the core theme templates so anything add there will be overwritten on an theme update.
You would need to install a child theme and within it's folder structure is a header.php file and this is where you would add your GA code. That way your child theme will not be overwritten by updates.
Yea brother, the problem isn't my coding. I've been doing that for 20 years. The problem is that I hate going into cPanel to make minor changes every time. Hate messing around in SiteGround. Would rather just do it through Appearance > Edit Theme option.
But, some darn plugin has removed that option from my WP side menu.
OK, now you've piqued my interest. Sounds like you know what you're talking about.
Here's the deal. I don't develop sites anymore, haven't in a decade. But, I still understand what's going on with respect to code, though not like I once did. I am, in fact, an SEO strategist and site optimizer.
I've got a situation where I can't integrate Console into Analytics. I have an analytics account set up. And, I have a console account setup. But, I need to add one little snippet of code into the head of the core theme html page to integrate Console into Analytics.
The head of the development team is really anxious about letting anyone have access to SiteGround outside his department and I don't blame him. But, I have to do my job and part of that means tracking individual pages and that requires integrating Console into Analytics.
I don't want to go whining to the CEO and chuck anyone under the bus. That's a bad start to a new job.
I just want to add one little snippet of code to the head of the core theme .html page. How do I do that without a child theme and without access to Appearance > Theme Editor?