I am supplementing my previous email with the following information.
'Integro' = IN-te-gro; stress on the first syllable (first person singular present of 'integrare').
Use when you realise you forgot to include something in a previous email and need to add it without sending a completely new message.
'Integrare' in this context means to supplement or add to. It is more elegant than saying 'Ho dimenticato di...' (I forgot to...). It frames the additional information as a natural complement rather than an oversight.
Aggiungo che...
I would also add that...
Simpler and very common for adding a forgotten point
In aggiunta a quanto già comunicato,
In addition to what has already been communicated,
More formal and complete
Con riferimento alla mia email di questa mattina, preciso che...
With reference to my email this morning, I would like to clarify that...
Used to add a clarification or correction
VAT in Italy ('IVA — Imposta sul Valore Aggiunto') is 22% for most goods and services. Always clarify whether a price is 'IVA inclusa' or 'IVA esclusa' in business emails to avoid disputes.