預金口座を開く。

English Translation

I’ll open a bank account.

  • bank account = 銀行口座
  • savings account = 預金口座

A savings account is just one of purposes of a bank account. We usually say 銀行口座を開く (ひらく), or more frequently 銀行口座を開設する (かいせつする) rather than 預金口座を開く.