Hello,
I am switching from one theme to a completely different one, I don’t mean just changing the demo. I am moving from Avada to Soledad - Multi-Concept Blog/Magazine/News AMP WordPress Theme.
I already have a lot of content on my site and wondering if the switch will delete everything, will I need to do everything from scratch?
Thank you! 
Hello 
No. All your content will still be there.
Hello,
So everything will be automatically imported yes?
Thank you 
Hello,
The theme affects only the presentation part, all the data in your website will be there no matter which theme you change to. You might face some issue with design though.
Hello,
Usually changing a theme will only change the style of the site. This includes:
But the pages will not be removed (including posts or any other custom posts and medias). So the old content will not be lost. But some of their style will be.
Nowadays theme authors are forced to add their custom shortcodes, widgets in a plugin (as I know Avada already comes with Avada Core). So if you don’t remove the Avada Core your page content will work even after migration.
what issues for example are we talking?
to what extent would I need to do juggling around and tidying up, I am assuming the quality of the images will not be ruined, pixelated etc?
How do I remove Avada Core?
Also, do I need to remove my old theme first before installing the new one, or the other way round?
Issues in design and if your previous theme uses any custom shortcodes and widgets in a plugin they won’t work with the new theme.
I suggest you create a testing site using a plugin like Duplicator and see how it goes.
Removing old theme isn’t needed. You just have to deactivate it and activate the new one.
how can I deactivate it?
will I need to change or delete any plug-ins?
Go to Appearance > Themes, You’ll find all the themes that are installed on the site, just activate the one you want. Once the new theme is activated the old theme is deactivate.
Then I am guessing the total wordpress upload capacity will get freed up more right? (since there is an upload limit).
No. There’s a limit to the file size you can upload at a time (for many servers its very less) but the total amount of files you can upload if fairly large for most types of hosting.
Going by our discussion I suggest you hire someone to do it for you, you can either contact me here or hire someone from envato studio.
If want to do it by yourself first create a replica of the live site then try changing the theme.
hiring would cost a fortune so it can’t be an option at the minute, so how can I recreate the live site?
If shouldn’t cost a fortunes. If should cost somewhere around the cost of a typical wordpress theme.
Recreating a live site can be easily done using the duplicator plugin, you can find it here - https://wordpress.org/plugins/duplicator/.
After you install the plugin it checks if the server has some parameters setup as it wants then gives you two files, you copy those two files and put them in the new location and open the installation file and viola you have a replica of your site.
right so let me get this right, as it my current site is (without deactivating/installing anything) I straightaway install the plug-in suggested and then I will see two files in my dashboard?
Not in dashboard, the plugin has it’s own area (like all plugins) it’s a 3 step process, step One it checks for its required parameters, Step Two it asks you to generate the files, On Step 3 it gives you links to download the files.