<form name="new_job" action="/jobs" method="post" accept-charset="utf-8">
  <input type="text" name="job[job_title]" placeholder="Job title"> at
  <input type="text" name="job[company_name]" placeholder="Company name">
  <br>

  <label for="job[job_description]">Job Description</label><br>
  <textarea name="job[job_description]">Your life story goes here. Keep it concise.</textarea>
  <br>

  <input type="submit" value="Add job">
</form>

<form name="new_job" action="/jobs" method="post" accept-charset="utf-8">
  <input type="text" name="job[job_title]" placeholder="Job title"> at
  <input type="text" name="job[company_name]" placeholder="Company name">
  <br>

  <label for="job[job_description]">Job Description</label><br>
  <textarea name="job[job_description]" placeholder="Your life story goes here. Keep it concise."></textarea>
  <br>

  <input type="submit" value="Add job">
</form>

Use placeholder attribute of textarea
Use placeholder attribute of textarea
