The Photoshop flame filter is found via the filter menu and render category
It produces amazing fire themed designs in 1000s of different styles. You can manipulate the settings as well as the required path.
You need to create a path, this can be done by using a custom shape in path mode or using the pen tool in the same mode (as well as the curvature tool). You can create all kinds of basic designs such as a line but you can also create lovely curved designs as well as wavy designs and more. Just don't make it too long as it will cause the tool to pop up a message and you won't be able to use it.
Presets are included with the tool. You can select the default as well as setup your own presets
You can create very small images but you can set the length to the maximum and create amazing long designs. You can also click the randomize length to randomize the lengths. The randomize makes the fiery look far more convincing
You can create very short or thin artworks but you can also ramp up the width field and create far more intense dense art
You can modify the angle of the design (sadly there is no random feature there) say 45 degrees etc
You can change the color of the fiery elements to a solid color via the 'custom color' option. It is a pity that it does not use the gradients etc. Personally, I prefer just to modify the end result using adjustments as an adjustment layer such as hue / saturation or LUTs etc
All kinds of amazing designs can be created by clicking into the advanced panel. You can change the turbulence as well as jag and opacity as well as complexity and alignment and style and shape and randomize the shapes and arrangement. There are a lot of options and by changing some of the settings the result doesn't really end up looking like anything but it can be used to create some truly abstract designs.
You can set a high opacity setting in advanced and the image will be totally blown out by the effect, set the opacity to low and the color and effect will be very subtle such as a mist or subtle fiery designs.
This is an unusual one. The result of a high setting is a far less convincing design, set it low for a better value
You can create a new layer (layer menu and new layer) and apply it to that and then change the settings or perhaps change the underlying path design (use the direct selection tool to move the point or points before re-applying to a new layer). Repeat this with multiple layers and with the multiple effects, you can then combine them in all numbers of ways using difference, darken, lighten etc blending modes. The result can look quite painted
You can apply the effect but you can also fade it via the edit menu and fade and change the opacity as well as the applied blending mode such as fading to color burn which I think actually looks a more convincing look.
You can re-color the design in millions of ways by using the camera raw or use the image menu and adjustments or the live adjustment layers
Best to create the image on a layer and then go to the layers menu and smart objects and convert. You can modify the effect as well as distort it using a variety of tools such as twirl, pinch etc to tweak the fire in all kinds of ways and they will all still be editable via the layers panel (and you will able to delete them as well)
Create a black background. Go to the curvature and place in path mode and then add a couple of points with a slight curve from bottom to top of the image (though you can make endless variations of this). With the path active, go to the effect and render menu and apply using the type 'candle' . You can also set randomize shape in advanced for some variation. You cal also use the direct selection tool to manipulate the path such as changing the bend of the path and the re-apply. You can also generate all these candles on layer and then they can be quickly moved and rotated and scaled as well as duplicated and have blur effects etc applied. You can also add into the mix the powerful smudge tool that can be used to drag the pixels up and down to create some variation in the candle art