Remove index.php in permalinks?

I’ve recently installed this plugin for a website that helps rescue dogs get adopted. I noticed that it adds a index.php in the permalinks, which wasn’t there before using the plugin, and as we promote the dogs often on social media, it would be great to have these links be as short as possible. At the same time, there are already a lot of links out there on social media that do include the index.php so would be great if the page could be found both ways (with and without the inclusion of the index.php part). Any ideas? Thanks!

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