Log in to your Plausible Analytics account and in the top right menu, click on your accout name and choose "Settings" to enter your account settings.
To change your subscription plan, find the "Subscription Plan" section and click on "Change plan".
Select your new subscription plan and choose if you want to pay on a monthly or yearly basis. Then click on the "Preview changes" button.
Next up, you will see your new charge that is due now. This is a pro-rated amount which reflects the amount you have paid on your previous subscription and the amount of time until that subscription was supposed to expire.
A negative value for immediate payment amount represents a credit balance. This credit amount will automatically be used to deduct your upcoming payments until it is depleted.
You will also see the date of the next subscription renewal and the amount of that payment. Your subscription will be renewed automatically and you can change or cancel your plan at any time.
Click on the "Confirm plan change" to confirm the new subscription.