Campaigns are made up of Activities. Those activities have their own goals, whether it is the main donation amount you wish to collect, the Crowdfunding and Peer-to-Peer Fundraising, or the amount from your Corporate Sponsorship form, etc.
If you want to adjust the campaign's goal, you will actually change the goals within each activity within the campaign, so it is accurately represented in the campaign and on the campaign tile.
Crowdfunding and Peer-to-Peer Fundraising
If the activity is a Crowdfunding and Peer-to-Peer Fundraising Activity, then you can set or change the goal on the Setup / Keyword page.
Text to Donate
For other Activities, such as a Text to Donate Activity for an event, the goal is found on the thermometer page.
Go to the Fundraising Thermometer section on the left, within your activity.
Click on the Shared tab then Event Details section below the Theme to provide a dollar amount for the Goal of the event.
The donation goal amount is used when calculating the percentage of the thermometer filled as well as the options given in the Display Options section on the Screen tab.
The Goal, defaults to $0. As soon as you change the amount, your goal will also update in your campaign.