The filter must be applied to an element that has width or height measurements. For example an image, table, table cell, div, span etc. You cannot, for example apply it to the <p>, H3, <b>. Because an exact measurement is required one can enclose the tag within a <div> or <span> and define the width or height, or both. For example to apply the wave filter to a line of text you could do this:

Stand alone text example:

<div style="width: 100%; filter: wave(add=false, lightstrength=50, phase=10, strength=3, freq=3,);" <font face="Arial black" size="6" color="blue"><b>This is blue text with wave effect applied</b></font></div>

Applied to an image

<img style="Filter: wave(add=false, lightstrength=50, phase=20, strength=10, freq=8,);" src="image.jpg" align="center" width="75" height="100" alt="effect applied to an image">

Altering the filter

Just play around with the numbers and see what has changed. The freq gives you the number of waves. You can change add=false to add=true for a different effect.