Adobe Acrobat's Auto-Complete function saves interactive form data and offers suggestions on subsequent forms to save you the unnecessary time of filling in repetitive data. The feature has two modes. The Basic mode works similarly to your browser's drop-down suggestions in that as you type, probable matches are presented. The Advanced mode takes this a step further by automatically filling in values that Acrobat deems to be highly probably matches. Although you have the option to completely disable this feature, consider reverting to Basic mode to retain functionality without having fields automatically populated.
Click "Edit" (Windows) or "Acrobat" (Mac), select "Preferences" and then choose "Forms" in the Categories panel.
Deselect "Remember Numerical Data" in the Auto-Complete section if you only wish to disable the feature for numbers. Although numbers usually entails reusable data, such as telephone numbers, product IDs and Social Security numbers, it also remembers calculated figures, which means it potentially produces a long list of figures you're unlikely to use again.
Click the "Auto-Complete" drop-down menu and then select "Off" to disable the Auto-Complete feature entirely. Alternatively, select "Basic" if you want to retain the feature's function while preventing data from being automatically filled. Click "OK" to save your settings.