What's the correct place for label?

Hi everyone. I get that labels are useful to wrap inputs , and that they make the various inputs more accessible. My question is: a label is related with its content trough wrapping (the input is nested within it) or trough the for-id bind relation?
For example:

<form action="random_site">
 <label for="web_sites">Choose a website:</label> //the label wraps a text

<select name="webSites" id="web_sites">
  <option value="FCC">FreeCodeCamp</option>
  <option value="GitHub">GitHub</option>
  <option value="Google">Google</option>
  <option value="Codewars">Codewars</option>
</select> 
<input type="submit" value="Submit"></label>
</form>

//whereas in a radio-button/text form 

<form action='php'>
<label for='red'>
  <input type='radio' name='colors' id='red' value='red'>Red
</label>
<label for='blue'>
<input type='radio' name='colors' id='blue' value='blue'>Blue
</label><br>
<input type='text' placeholder='Insert test' required>
<label for='red'>
<button type='submit'>Click</button>
</form>

The text input send its value when the submit button that stands for the whole form is pressed right? Can I have a specific button for it? Also, can I have a form within a form? I mean, outer form collects its data and sends it to a server whilst the one nested sends it to another oneā€¦ thanks for your attention!

Hi everyone. I get that labels are useful to wrap inputs , and that they make the various inputs more accessible.