The ripple filter in Affinity Photo can be found in the distort sub-menu of the graphics application (which can be found in the filters menu) but this should be noted is a destructive effect so you will need to use the undo to remove it, if required. The effect can also be found in the layer menu in the live layers (non destructive effect) and this is applied to the current layer or all layers
Select from menu and set the origin or focus point for the effect and this can be done by using the cursor by positioning over or outside of the current image and layer. You can also set the intensity for the effect and click Apply. Set it to low for slightly bigger waves around the origin point. Set it high for very extreme thin lines and distortions at the center point. Set it to about 40 and you get the best wavy effect (truly wish there was a wave tool in the application), not too mild and not too extreme.
The effect can also be used in Designer and publisher if you have those as well, though you still need the main photo application. Go to the photo persona to use this effect. You can also use the edit in Designer etc commands to use the same effect in those applications
You can use it combined with selections so you can create a quick selection and then apply the effect to that selection only. You can set the focus or origin point within the image as well as outside of the image as well as outside any selection
You can also use it with channels so you can go to the channels panel and select the red channel and then apply the effect to that and then you can go to the green channel and apply it again but to a different origin point as well as different intensity. You can also apply it multiple times to a single layer and also completely ignore the other channels. You can also change the image mode / color so you can apply the effect to cyan and magenta etc if using CMYK etc
You can also use it with multiple layers. You can also use it with shapes as well as text. You can use any of the shapes that come with the application such as the cloud tool as well as the rectangle and ellipse and many other tools. You can select part of the image using the elliptical or rectangular marquee tool and copy and paste and then apply effect to only that layer. The rest of the image is not modified and the great thing about layers, you can move them and re-size and rotate them and also delete them later on.
You can use the tool with any text as well so if you create paragraph text or artistic text then you can use it with that as well. The effect does mean the text is turned into a pixel layer so the text will no longer be editable. So if you wish to apply it to the text then make certain you have run the spell check, You can use the live option and that does mean the text will still be editable
You can also combine the effect with others such as the deform and mirror effect and you can create all kinds of amazing wavy designs using this approach.
You can also record the effect steps using the macro feature and this can be found via the view menu and studio and macro (as well as library). The macro steps can then be applied to any other type of layer such as text and more. You can also click the add to library button on the macro panel to save the macro and then use it again and again in future projects.
You can also use the non destructive effect via the layer menu and live layers and distort. This can then be modified at any point and applied to any number of layers or all the layers below the effect. This can also use the blending mode as well as the opacity for the effect as well. You can also go to the layers panel and double click the entry and change the origin point / focus point as well as the intensity as well as the blending and opacity.
You can also use the linked layer duplicate feature in the layer menu and create multiple linked effects. Any modification to a layer by the effect will be reflected in all the other layers. So select one and apply it, perhaps using a subtle low setting, and all the duplicated linked layers will change at the same time. You can also unlink certain properties as well.
You can also use the effect with the layer menu fade which means you can modify the strength / intensity (it does not modify the origin point) to create subtle waves as well as more intense ones as well as a ripple with a different blend to the current layer. You can also blend in darken / difference / linear / color burn etc
You can use the pattern layer feature via the layer menu from any selection such as a shape as well as an image and the image can be one modified using the ripple. To get the best effect, I would suggest that you select the mirror feature in the top left. You can then also continue to use it with the layer and you can also rasterize the layer and create amazing distortions with that as well