If you have an online account with your financial institution, you can probably sign in to your account and download your Form 1099-DIV.
Do you have a year-end statement or other documents that show the amount of dividend income you had for the year? A year-end statement shows a summary of your dividend and capital gain distribution income for the year. If you know how much dividend income and capital gain distribution income you had, then you can go ahead and enter it. You don't need to have a Form 1099-DIV to file your tax return. You can also contact the financial institution that issues the Form 1099-DIV and ask about the Form 1099-DIV.