You can change the text / font size on your iPad by navigating to Settings > General > Text Size. Just drag the slider to adjust the size. This will only work for apps that support Dynamic Type, such as Notes and Contacts, not web pages and other applications.
You can also make the text / font on your iPad bold by navigating to Settings > General > Accessibility and tapping the Bold Text slider to green. This is also the section where you can turn on other features such as Speak Auto-text and Subtitles & Captioning.