check the manual that corresponds to your MariaDB server version for the right syntax
<p>I am trying to change the root password for PhPMyAdmin which has 10.1.13-MariaDB
 by typing the following in the SQL tab and hitting on the <code>Go</code> button:</p>

<pre><code>ALTER USER
  'root'@'localhost' IDENTIFIED BY 'mypass'
</code></pre>

<p>I get this error:</p>

<pre><code>Error
SQL query:


ALTER USER
  'root'@'localhost' IDENTIFIED BY 'mypass'
MySQL said: Documentation
</code></pre>

<blockquote>
  <p>1064 - You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'USER
        'root'@'localhost' IDENTIFIED BY 'mypass'' at line 1</p>
</blockquote>

<p>I followed <a href="http://dev.mysql.com/doc/refman/5.7/en/resetting-permissions.html" rel="nofollow noreferrer">this tutorial</a> on MySQL website:</p>

<blockquote>
  <p>Create a text file containing the password-assignment statement on a
  single line. Replace the password with the password that you want to
  use.</p>
  
  <p>MySQL 5.7.6 and later:</p>
  
  <p><code>ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass'</code></p>
  
  <p>MySQL 5.7.5 and earlier:</p>
  
  <p><code>SET PASSWORD FOR 'root'@'localhost' = PASSWORD('MyNewPass');</code></p>
</blockquote>

<p>Here are some screenshots:
<a href="https://i.stack.imgur.com/GaOnK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GaOnK.png" alt="enter image description here"></a></p>

<p><a href="https://i.stack.imgur.com/MIkNj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/MIkNj.png" alt="enter image description here"></a></p>