Interest rates are at historic lows.
Joe buys a bond with a par value of $1,000, mature in four years paying a coupon rate of 4 percent annually. That means he'll receive $40 a year or $160 over the lifetime of the bond if he holds the bond until maturity.
Anne holds off, because she thinks that interest rates will rise in the next few weeks. Sure enough a new bond is now offering a coupon rate of 5 percent, meaning that Anne will receive $50 dollars annually, if she decides to go ahead and purchase bonds now.
Anne can either buy the new bond for $1,000 at 5 percent, or she can buy Joe's bond at a reduced price, because why would she pay $1,000 for a 4 percent coupon rate? She wouldn't, so she could purchase Joe's bond at a discount.
In this example, Anne could purchase Joe's bond at a discounted rate of $965. As you would guess, if interest rates decreased to 2 percent and Joe wanted to sell his bond, his could sell at a premium or above par value. This is just another way to illustrate the inverse relationships between interest rates and bond prices, and remind you to consider the ups and downs before jumping into the bond market.
BUT if Joe doesn't sell his bond, he loses lose nothing, as he continues to receive his $40 in annual income, and he gets all his cash back when the bond matures. So in that case, the decline in market value doesn’t make any difference.
However, there are similarities and important differences in how bonds behave vs bond funds.
You will find people who argue that bonds are a bad investment in the short run, but still a good investment in the long run. But there are few if any alternatives. Some people recommend dividend paying stocks to replace bonds, but that comes with an increase in risk & volatility, there's no guarantee dividend paying stocks will outperform bonds despite the current interest rate outlook.
Just do a search on bond dilemma or bonds interest rates, etc.