In fact, the addition of a "checkmark" or any other visual "tick", nowadays, is linked to the use of a font that allows not only to achieve the desired effect, but also and especially to remain compatible whatever the device, and / or operating system.Moreover, some solutions provide an accessible alternative, in case of screen reader.Among the various solutions, there is the oldest (in terms of popularity) font awesome, but there is no lack of solutionshttps://fontawesome.com/https://www.flaticon.com/https://feathericons.com/https://iconscout.com/uniconshttps://nucleoapp.com/ and this list is far from being exhaustive The use is very simple, first of all, and depending of the type of the supplier that you will use, you will have to either link the font source to your project, or use a JavaScript script, to your project.Most of solution get a free use at basic steps... and volume of available icons. then you will have to search and use the special HTML mark to use the appropriate icon. in your example, and if one use UNICONS suplier... free to you to use anyone you like... that is just an easy exemple (some solution can be complex for the first use) soGet the link to be include in your project from https://iconscout.com/unicons/getting-started/thinline in that case add to you HEAD HTML the following line   then explore the library to find the mark that you look for ... from https://iconscout.com/unicons/explore/thinlinein this lib the chekmark is named "check", type it in the search field, you will have different solution... and depending on it, you will get the HTML tag to be added ... in the basic and classic display it is   but you also have different other context as etc...  does this helps you ?

First off, you should realize that you don't actually need to use HTML entities – as long as your HTML document's encoding is declared properly as UTF-8, you can simply copy/paste these symbols into your file/server-side script/JavaScript/whatever.

Having said that, here's the exhaustive list of all relevant UTF-8 characters / HTML entities related to this topic:

• ☐ (hex: ☐ / dec: ☐): ballot box (empty, that's how it's supposed to be)
• (hex: ☑ / dec: ☑): ballot box with check
• ☒ (hex: ☒ / dec: ☒): ballot box with x
• ✓ (hex: ✓ / dec: ✓): check mark, equivalent to ✓ and ✓ in most browsers
• (hex: ✔ / dec: ✔): heavy check mark
• ✗ (hex: ✗ / dec: ✗): ballot x
• ✘ (hex: ✘ / dec: ✘): heavy ballot x
• 🗸 ( hex: 🗸 / dec 🗸): light check mark (poorly supported as of 2017)
• ( hex: ✅ / dec: ✅): white heavy check mark (mixed support as of 2017)
• 🗴 ( hex: 🗴 / dec: 🗴): ballot script X (poorly supported as of 2017)
• 🗶 ( hex: 🗶 / dec: 🗶): ballot bold script X (poorly supported as of 2017)
• ⮽ ( hex: ⮽ / dec: ⮽): ballot box with light X (poorly supported as of 2017)
• 🗵 ( hex: 🗵 / dec: 🗵): ballot box with script X (poorly supported as of 2017)
• 🗹 ( hex: 🗹 / dec: 🗹): ballot box with bold check (poorly supported as of 2017)
• 🗷 ( hex: 🗷 / dec: 🗷): ballot box with bold script X (poorly supported as of 2017)

Checking out web fonts for tick symbols? Here's a ready to use sample for the more common ones: A☐BC☒D✓EF✗G✘H -- just copy/paste this into your webfont provider's sample text box and see which fonts support what tick symbols.