Looking on the internet deeply has found these results:

attach to is the most popular phrase on the web.

attach into 136,600 results on the web	attach to 135,600,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
To attach the contents of this directory, either attach the files in this directory individually, or create an archive of the directory and attach it. These people attach a part of themselves To their collection. By selecting Attach Attach File you can open the File Selection Dialog Box; here you can choose the file you want to attach. We have stressed, Mr Hatzidakis, the importance which we attach to translating agreements into an efficient organisation on the ground, well in advance of payment of the first appropriations by the European Union for the new programming period. Her attorneys threatened to attach his negative. Most political groups attach high importance to this. Attach detailed list if multiple shipments. Member States shall be able to attach translations of any European Arrest Warrants they attach to an alert for arrest and if necessary in separate binary files.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

attach into

136,600 results on the web

attach to

135,600,000 results on the web

More popular!

To attach the contents of this directory, either attach the files in this directory individually, or create an archive of the directory and attach it.
These people attach a part of themselves To their collection.
By selecting Attach Attach File you can open the File Selection Dialog Box; here you can choose the file you want to attach.
We have stressed, Mr Hatzidakis, the importance which we attach to translating agreements into an efficient organisation on the ground, well in advance of payment of the first appropriations by the European Union for the new programming period.
Her attorneys threatened to attach his negative.
Most political groups attach high importance to this.
Attach detailed list if multiple shipments.
Member States shall be able to attach translations of any European Arrest Warrants they attach to an alert for arrest and if necessary in separate binary files.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.