Select the Ellipse Tool (M) and create a Circle. Click in a spot and drag diagonally while holding the Shift key.
Center it by clicking on the Horizontal and Vertical Align Centre in the Alignment Panel (Top menu).
Step 2: Add the text to the path
In general, you need to make sure that the path is selected before clicking on it with the Artistic Text Tool in order for the text to warp around it.
As you hover your cursor over the edge of the path you will see the cursor icon change to a letter T with a wave under it.
Click on the path roughly where you want to place your text and type what you want.
Step 3: Adjust your text
Depending on where you clicked, the text may be on the inside or the outside of the path. To change this, just click on the Reverse Text Path button on the Top menu.
Choose the Font you want to use and the size of your text.
To adjust the position of the text. You will see two handles, one green and one orange. The green one represents the starting point of the text and the orange one represents its end point.
To center the text to the top part of the circle (for example), drag the green handle until it snaps on the left side quadrant (blue dot) and do the same with the orange handle but place it on the right quadrant. Now, change the text alignment to the Center and your text should be centered on top of the circle.
If you want to add another line of text, place the cursor at the end and hit Enter. This will add more text inside the circle.
As before, type what you want, move the green and red levers to center the text.
To add more space between letters, select the text by clicking three times on top of it and press the Right Arrow key as many times as you need while holding the Option/Alt key to Loosen the spacing and create the separation. If you want to decrease the separation, just hold the Option/Alt key and click on the Left Arrow key instead.
If you want to move the text from the inside of the circle to the outside or vice versa. Select it and adjust the Baseline in the Top menu.
To decrease or increase the space between individual letters, place the cursor between them and use the same method as before.
Step 4: Convert text to curves
Once you are happy with your text, select it and head to Layer > Convert to curves or click on the Convert to Curves button on the Top menu.
Second example, place text on a wavy or curved path
Step 1: Create the path
Use the Pen Tool (P) to create a wavy or curved path (or any other shape).
Step 2: Add and adjust your text
As before, make sure that the path is selected and with the Artistic Text Tool click on the path roughly where you want and type your text. Choose the Font and give it the size that works better.
Arrange the green and orange handles and center your text.
You can modify the path using the Node Tool (A) and clicking on the one you want and adjust it.
If you want, you can convert your text to curves like in Step 4 of the first example.
Third example, Warp text workaround
There’s no Warp tool in Affinity Designer, but there is a workaround that can be used to achieve similar results. This workaround may not work with every font (it works better with Sans Serif, chunkier fonts and not so great with Serif, Rounded and Script fonts) so you should keep that in mind when you choose the font to work with.
Step 1: Type your text
Select your Font and type your text.
Step 2: Create the shape for the warp
Use the Pen Tool (P) to create a line of the same length of the text. With the Move Tool (V), drag it down while holding the Shift key.
Then, use the Node tool (A) to create a central node. Pull it up holding the Shift key.
Make the node Smooth clicking on the Control Panel (Top menu).
Hold Command/Control + Shift while dragging one of the handles so you pull both sides uniformly and in a straight line and create a curve.
Make the Curve a bit larger than the text.
Step 3: Transform your text
Once you are happy with every aspect of your text, convert it to curves (Top menu). And Ungroup it (Top menu).
With the Move Tool (V), select and drag down the bottom of your letters until they touch the curved path beneath.
If some letters need additional tweaking, use the Node Tool (A) to drag the individual nodes down. Hold the Shift key while doing this to follow the same angle. Adjust the handles if needed to make the shape of the letters more harmonic.
Select all the letters and click Add in the Geometry Panel (Top menu) to join them together.