Upgrade my iPhone storage

1.

You cannot increase the iPhone storage.

You can free up iPhone device storage see this Apple articles below:

If you need more space for an update on your iPhone, iPad, or iPod touch

If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support

How to check the storage on your iPhone, iPad and iPod touch

How to check the storage on your iPhone, iPad and iPod touch – Apple Support (UK)

Clear Other storage on your iPhone or iPad

Clear Other storage on your iPhone or iPad - Apple Support

2. 

If you wish, you can upgrade the 5 GB free iCloud.

See -> What's the difference between device storage and iCloud storage?

What's the difference between device storage and iCloud storage? - Apple Support

See also the following Apple articles:

Upgrade to iCloud+ -> Upgrade to iCloud+ - Apple Support

iCloud+ plans and pricing -> iCloud+ plans and pricing - Apple Support

How to use iCloud on iPhone -> How to use iCloud on iPhone – Apple Support (UK)

Manage your iCloud storage -> Manage your iCloud storage - Apple Support

Hello ~ Do you mean upgrade your iOS or buy more iCloud storage? As far as upgrading your iOS you can only upgrade to 12.5.7 but no further if that is the case you need a newer iPhone. In the case of upgrading iCloud storage or managing your device storage…

What's the difference between device storage and iCloud storage? - Apple Support

Post back if needed and take care.

~Katana-San~

It is not possible to add storage space to an iPhone.

If you need additional space, you will need to move or delete existing content.