Is it correct to put foreign keys on the ID field?

Question

PostgreSQL

There are 2 tables
Table 1
id - automatically generated field
field1 - unique table field
Table 2
id - automatically generated field
table1_field1 - link to a unique table field 1. Not unique in the table 2.
field2 - unique table field
How to properly organize a relationship between tables?
Will there be a difference between the foreign key of the table1_field1 field of table 2 on the id and field1 fields of table 1?
id is numeric and field1 is a string field. Could it matter?

Answer 1

Apparently your id is a surrogate PK. If there is a unique field1 field, then it makes sense to keep a surrogate PK in the table only for the sake of human convenience, otherwise it is completely unnecessary. Table 2 is in a similar situation.
If one-to-many, then table1_field1 is sufficient.
What difference are we talking about? In a wording like yours, no, it won't.
field1 isn't a UUID by any chance? In most cases, there will be no difference. All the same on them to hang up an index.