I wanna create a eCommerce Website for that I want to buy WordPress themes but before purchase I want to know which is the best eCommerce Plateform WordPress or Joomla.

Welcome Linda
The short answer is it depends ... sorry I couldn't resist that

Some questions first up

What level of buyer are you targeting? - General anyone or specific niche? Makes a huge difference
How many items are you looking to have in total?
How many categories of items?
What is your skill level?
Will there be more than one person adding content/managing the site?
How often will you be updating your items and associated content?
Are your sales for digital or physical products? If physical is postage critical?
How many buyers would you envisage buying on a weekly basis?

Whether it's Wordpress or Joomla they do not have any ecommerce enabled by default and use ecommerce/shopping cart addons.

Joomla has a number of these as does Wordpress and the functionality of the contributions differs markedly with both systems.

I've been involved with things like Joomla and Wordpress since before they became popular and my comments are based on working with numerous people with different level of skills. Wordpress from my perspective is a blogging tool and one that has some limited content management and ecommerce can be problematic. Joomla is a more serious and robust platform for delivering a range of content and ecommerce functionality.

All of this needs clarification before you choose a template or a site that not only sells templates, more importantly supports what you purchase..

This place absolutely rocks with support for the templates ... that comes from 18+ years of using CMS's

Think that will do for starters.
Keep asking here for clarificationa dnw ecan assist.

Sorry everybody

We've had a server glitch and the database backup isn't quite up to date as it should be

So we've lost some forum replies

I can post information here from my emails if needed

Cheers
Paul

I tend not to see Wordpress and Joomla as competitors. They do different things.

Wordpress is primarily a blog, with recent iterations adding a duct-taped static page functionality onto it. For a well defined project that doesn't need to challenge the limits of a theme, Wordpress can work rather well.

Joomla is a dynamic environment with exceptional extensibility, with much more vast ability to scale. It is not, despite the boilerplate you read everywhere, more complex to use than Wordpress; personally, I find it more facile and better organized. What becomes more complex is your needs, which is why one might choose this platform to begin with. The competition is the universe of other large-scale CMS's such as Drupal, Magento, .NET.

Cloud services such as Shopify can work rather well, and my work has included both building Shopify sites, and moving sites out of Shopify (once the store becomes large, the add-on costs of plugins and customized templates become prohibitive). Every year though, I get a Christmas surprise: an affiliate check from Shopify for the active stores I've developed. Nobody from WP or Joomla sends me a year end cheque.

Thanks Blueshift

Is it a big cheque - buy many IPA with it?

I've found Wordpress security much more of an issue - whenever I've left a test site doing nothing for a few months - bang hacked

I expect with Wordpress being much the bigger beast that hackers do target it more

Cheers
Paul

WP security is swiss cheese for sure. None of the sites I manage have user accounts - only a few content managers and writers. I install Wordfence, and a parallel program that blocks out ranges of IPs - and still, these WP sites are getting pummeled all day, every day. The lockout settings I apply are ruthless. You are in on the first try or you simply cease to exist. The admin emails are themselves constructed like passwords, so good luck. You could try my phone. Oh, wait. It's not listed.

If a client wants comments, I put them in Joomla where I can let Disqus deal with the miscreants in the cloud... I keep them completely out of the site.

What do you install alongside Wordfence?

Disqus is good for that

Cheers
Paul

Besides Wordfence, I use WP Security Audit Log - on one site, I located the source of an attack - and walled him out - with this plugin.

Thanks

I need to raise my game with Wordpress

Cheers
Paul