If you need to represent a check mark, aka tick mark, or an x mark, aka cross, x, ex, exmark, and into mark, or a checkbox, aka check box, tick box, and ballot box, which someone can checkmark, on a webpage, there are a number of HTML codes that can be used to do so. The codes can be represented in decimal or hexadecimal format depending on your personal preference.
|☑||ballot box with check||☑||☑|
|☒||ballot box with x||☒||☒|
|✅||white heavy check mark||✅||✅|
|✔||heavy check mark||✔||✔|
|✕||large multiplication sign||✕||✕|
|✖||heavy multiplication sign||✖||✖|
|⨯||cross product, also known as Gibb's vector product||⨯||⨯|
|✘||heavy ballot x||✘||✘|
If you see squares or question marks instead of the symbols, you may need an appropriate language pack installed to display the symbols.