Hi Sayo,
Welcome to Bytes!
Is the information that you want to upload/input in another database? If not, is it in a spreadsheet at least? There's a very simple way to import the data if it's already in a database or a spreadsheet, although you may want to format the spreadsheet or resave it with a different file extension prior to importing.
I mostly use Access 2003, so please forgive me if I'm off slightly on the location of the functions. That being said, if you go to the Office button (the color round button in the top, left-hand corner), there should be an option for Get External Data. From this menu you should be able to import your data from another database or spreadsheet.
If you're going to import from a spreadsheet, you may want to remove any unnecessary formatting or rows that contain headers as these may not transfer well during the import process. I've found that .csv files (.csv = comma separated value - a spreadsheet that contains values that are separated by commas) works well, but I won't get into that in case you're not familiar with it. You can always search the topic to learn more about it if you want.
Once you've chosen to import, you'll likely be prompted to identify how you want the data imported. Just choose the options that work best for you for your situation and the data should be loaded. Unless you're importing from another Access database, you'll probably have to import tables/spreadsheets one item at a time, depending on how many of each you have.
For the second part of your question, if you have individuals that are using a previous version of Access, in your case 2000, they won't be able to see any of the features that are new to Access 2007, such as the split form feature. The individuals would likely either need to upgrade to 2007 or you would need to develop a solution that is backward compatible with 2000.
Hope this helps and good luck,
beacon