Reiniel

you can use the add-on
WPBakery Page Builder (formerly Visual Composer) allows you to manage galleries from the frontend being admin of the site, it is simple and easy to understand.
Hope this can help you.

https://www.ads-software.com/plugins/vc-simple-all-responsive/

I recommend an easy way to achieve what you want, if you use contact form on your page you can use Multiline files upload for contact form 7, it allows users or customers to attach the form and it will arrive by mail.

Multiline files upload for contact form 7 allows user to attach unlimited files to upload to Contact Form 7 in wordpress website, User can upload unlimited files one by one, selected files will be displayed nicely on the screen. User can even delete the already selected file. Admin can set to send all attached files via email. All files will be combined into one ZIP file. This plugin is configurable. You can change the style of the buttons and files list.

https://www.ads-software.com/plugins/multiline-files-for-contact-form-7/

you can use this plugin https://www.ads-software.com/plugins/capability-manager-enhanced/
it work too
Hope this helps

Hello,

There is a plugin whose main function is to deploy a site from the development environment to a server, but do what you want to perfection, it package the site in an installable file via the web to give it to a third party, it is called Duplicator.
I hope this helps.
regards
https://www.ads-software.com/plugins/duplicator/

Hello, I think that this plugin may help you:

File Manager allows you to edit, delete, upload, download, zip, copy and paste files and folders directly from the WordPress backend. Don’t bother with FTP to manage and move your files from location to location. The most powerful, flexible, and easiest WordPress file management solution ever built!

I hope you solve your problem.

Hello, i have the same problem whit the template, you can helpme??