I create tables with user system than I create another user user1 , I give to him all privileges but when I connect with user1 I can't see or select the tables created by system
First of all, you should never ever create any objects in SYS or SYSTEM schema. Leave them alone, they own the database and - if you do something wrong, you might destroy the database.
As of your question: "all privileges" is quite broad term. What exactly did you grant to user1? You should've - as system
grant select on table_created_by_system;
and then, connected as user1,
select * from system.table_created_by_system;
In other words, you have to precede table name with its owner's name (system in this case). Other option is to create a synonym (public, perhaps?) and then you don't have to use owner's name.
I suggest you abandon it altogether. Drop tables from system schema and start over in user1's schema.