HTML to Wordpress - Can I change the URL structure?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  Tomas Ignatavicius: No difference
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  Craig Anthony: so adding these pages wont cause problems when i do the swap over ?
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  Tomas Ignatavicius: Craig Anthony Would only add value if the pages are useful for visitors. From a search engine perspective there is zero difference when they will discover and index pages. They will start ranking them only after they found then, and that`s it
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  Neil Cheesman: RE: It`s my belief that a safe transfer is to swap `as is` and not change any structure
  1. most html pages have a file extension of .html - Wordpress generally doesn`t have this extension. ie. example.html - on Wordpress example/
  so you need to do a 301 redirect for each of them like for like.
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  Craig Anthony: thanks neil - yes i discovered that a few weeks ago - thanks for pointing this out.
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  Craig Anthony: ie going from a 140 page site in html to a 5 page site in wordpress is considered a NO NO ! I should go from 140 pages html to 140 pages wordpress - then transfer - once transferred then i can change to 5 page in wordpress (if i wanted to ) Is this correct ?
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  Brenda Michelin: No. Crawl the existing site--you need to capture all of the URLs.
  Develop the new site, trying to keep the main page URLs identical IF your new structure fits that, if not, no bother.
  Map / 301-redirect all of the old URLs to matching URLs (or the most appropriate) IF the URLs have changed for that page.
  
  It will probably not be a 1:1 page ratio because the site structure may be different. You will probably not have 140 pages, but surely you would have more than 5? Is the site mostly blog posts?
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  Craig Anthony: Brenda Michelin thank you for your valued info - its for my art site . mostly product pages - no blog as of yet
  in fact i was aiming for 1:1 as i thought it was the safest way to avoid re crawl issues and drop off in traffic when the site finally gets tranferred
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  Brenda Michelin: Nice work! You need a full strategy for this re-do. You will be best served by using a few Custom Post Types and developing a few post template and post template archive pages. But, all of your URLs will change, for sure, so 301-redirecting is critical. You can do some redirection automation once you get your structure together.
  What theme/setup are you planning on?
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  Craig Anthony: Brenda Michelin so informative - thank you - well my plan (led by my belief)was to replicate my old site - then in future make a fancy site with new structure - i`ll be using elementor and astra theme
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  Craig Anthony: hmm not heard of CPT`s before - perfect timing - thank you
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  Craig Anthony: Brenda Michelin i have sent you a pm Brenda Michelin
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  Michael Martinez: Don`t create extra work for yourself. Having moved many sites from static HTML to WordPress, I always add new content via WordPress.
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  Craig Anthony: but am i right in thinking - i need to go from 140 page html to 140 pages in wordpress - ie do not change the structure until i have transferred to wordpress ?
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  Michael Martinez: Craig Anthony I don`t know. If you don`t want to include all 140 pages in the new content I don`t see why you couldn`t 301 redirect to an HTML sitemap page. I took a 20, 000-page static site down to a 100-page WordPress site in 2011. It`s doing fine.
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  Rituraj Shrivastava: You don`t need to go from 140 pages of html to 140 pages of WordPress. Just build your website`s new structure as you want on WordPress then 301 relevant html urls to their corresponding pages in wordpress. The left html pages can all be redirected to the homepage. Submit your site to google and you are good.
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  Craig Anthony: Well.... it appears I’ve been misinformed . Thank you guys