How long or detailed should our alternative text be?
Alt attributes should be accurate and as sufficient as possible. Usually, a few words will be descriptive enough but occasionally a sentence or two will be more appropriate.
For more information on how to create great alternative text, take a look at these examples.
Does it always have to be double quotes when we are writing anything inside a tag, can we use single quotes as well?
The general practice is double quotes when we hand write the code, but when generating code the circumstances will dictate. Personally, I always use double quotes on attributes and generate HTML strings with single quotes.
'<div class="something">content</div>'
or,
`<div class="${classname}">${content}</div>`