When you choose a Title, it is but a Template, and almost everything can be changed, and quite easily.
All you have to do is get the Title into the Titler, PrE's Title editing mini-app. Probably the easiest way is to choose the desired Title in the Title Display panel, from one of the displayed Templates. Then, it will be placed onto the Timeline automatically. PrE assumes that you want to place it where the CTI (Current Time Indicator) is located, and onto Video Track 1. Normally, this is NOT where I want the Title placed, so I just go to the end of the Timeline, moving the CTI to a point, just beyond any of my Clips. That is where it will then be placed. I can then Click+drag it, say to Video Track 2, and then to the point that I want. OK, we now have our Title Template placed, in this case, as an overlay, over the desired Video Clip, but remember, it is just the Template, and will have "placeholder" Text, usually along the lines of "Put Text Here," or similar syntax. We now want to change that to the desired Text.
In the Timeline, Dbl-click on that Title Template, and it will then open in the Titler. It looks almost like the Program Monitor, where we view our Timeline in playback, but if you look, you will first see a Toolbox, with the Selection Tool (arrow), the Text Tool (a T), a Color Palette, and then some other icons, for say aligning the Selected item (Text in this case) to the center of the Title. There will also be a series of Styles, represented by some text, but in color, with shadows, with Strokes, etc. Those will be important. Above those, there is an option panel, for the Text, with font, size, etc.
I normally use the Text Tool, that T from the Toolbox, and just Click+drag it over the Template's placeholder Text, to Select and highlight it. Now, begin typing. If you need to change that recently typed Text, just Select it again, with the Text Tool, and adjust the font, the size, or add a Style to it. If the chosen Style is the wrong color, then use the Color Palette, to change the Selected Text. Same if you wish to add, say an Outer Stroke. If there is not a Style w/ Outer Stroke already applied, just go to that Style display, choose such, and it will be applied. You can then go in and adjust the Stroke to suit.
Notice that I mentioned the word Select several times. You must Select the items in that Title Template to change them. For some, like a Shape, the Selection Tool (the arrow) is easier, and you can use it with Text, if you wish to move about the Text Box. If you want to change the Text, the Text Tool is better, IMHO.