required radio button in hmtl code example
Example: radio button required
One input with required attribute is enough.
<form>
Select Gender:
<label><input type="radio" name="gender" value="male" required>Male</label>
<label><input type="radio" name="gender" value="female">Female</label>
<label><input type="radio" name="gender" value="other">Other</label>
<input type="submit">
</form>